UserAgent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.41 Safari/537.36

Example URL:
https://apollodemo01.bbcollab.com/collab/ui/session/guest/8A5D356DFE1118DC9196240915B8CD23

Steps to reproduce the problem:
1. Join session as multiple participants
2. Talk with two participants having their mic on.

What is the expected behavior?
No echo should be heard.

What went wrong?
Sometimes, echo is heard by participants in the session. We were able to create dump for a session which had echo, dump available at https://drive.google.com/drive/folders/0BzQI6MLbgP7vRy1FYW1MT2xtZnM

Another example of echo is available at https://drive.google.com/drive/folders/0BzQI6MLbgP7vOVlDT1JicTFkNDQ

Did this work before? N/A 

Is it a problem with Flash or HTML5? N/A

Does this work in other browsers? N/A

Chrome version: 56.0.2924.87  Channel: stable
OS Version: OS X 10.11.6
Flash Version: Shockwave Flash 25.0 r0

Contents of chrome://gpu: 
Graphics Feature Status
Canvas: Hardware accelerated
Flash: Hardware accelerated
Flash Stage3D: Hardware accelerated
Flash Stage3D Baseline profile: Hardware accelerated
Compositing: Hardware accelerated
Multiple Raster Threads: Enabled
Native GpuMemoryBuffers: Hardware accelerated
Rasterization: Hardware accelerated
Video Decode: Hardware accelerated
Video Encode: Hardware accelerated
VPx Video Decode: Hardware accelerated
WebGL: Hardware accelerated
WebGL2: Hardware accelerated
Driver Bug Workarounds
add_and_true_to_loop_condition
adjust_src_dst_region_for_blitframebuffer
decode_encode_srgb_for_generatemipmap
disable_framebuffer_cmaa
disable_multimonitor_multisampling
disable_webgl_rgb_multisampling_usage
emulate_abs_int_function
get_frag_data_info_bug
init_one_cube_map_level_before_copyteximage
msaa_is_slow
pack_parameters_workaround_with_pack_buffer
rebind_transform_feedback_before_resume
regenerate_struct_names
remove_invariant_and_centroid_for_essl3
reset_base_mipmap_level_before_texstorage
rewrite_texelfetchoffset_to_texelfetch
scalarize_vec_and_mat_constructor_args
set_zero_level_before_generating_mipmap
unfold_short_circuit_as_ternary_operation
unpack_alignment_workaround_with_unpack_buffer
unpack_image_height_workaround_with_unpack_buffer
use_intermediary_for_copy_texture_image
use_shadowed_tex_level_params
use_unused_standard_shared_blocks
Problems Detected
Multisampling is buggy on OSX when multiple monitors are connected: 237931
Applied Workarounds: disable_multimonitor_multisampling
Unfold short circuit on Mac OS X: 307751
Applied Workarounds: unfold_short_circuit_as_ternary_operation
Always rewrite vec/mat constructors to be consistent: 398694
Applied Workarounds: scalarize_vec_and_mat_constructor_args
Mac drivers handle struct scopes incorrectly: 403957
Applied Workarounds: regenerate_struct_names
On Intel GPUs MSAA performance is not acceptable for GPU rasterization: 527565
Applied Workarounds: msaa_is_slow
glGenerateMipmap fails if the zero texture level is not set on some Mac drivers: 560499
Applied Workarounds: set_zero_level_before_generating_mipmap
Pack parameters work incorrectly with pack buffer bound: 563714
Applied Workarounds: pack_parameters_workaround_with_pack_buffer
Alignment works incorrectly with unpack buffer bound: 563714
Applied Workarounds: unpack_alignment_workaround_with_unpack_buffer
copyTexImage2D fails when reading from IOSurface on multiple GPU types.: 581777
Applied Workarounds: use_intermediary_for_copy_texture_image
Multisample renderbuffers with format GL_RGB8 have performance issues on Intel GPUs.: 607130
Applied Workarounds: disable_webgl_rgb_multisampling_usage
Mac Drivers store texture level parameters on int16_t that overflow: 610153
Applied Workarounds: use_shadowed_tex_level_params
Limited enabling of Chromium GL_INTEL_framebuffer_CMAA: 535198
Applied Workarounds: disable_framebuffer_cmaa
glGetFragData{Location|Index} works incorrectly on Max: 638340
Applied Workarounds: get_frag_data_info_bug
glResumeTransformFeedback works incorrectly on Intel GPUs: 638514
Applied Workarounds: rebind_transform_feedback_before_resume
glTexStorage* are buggy when base mipmap level is not 0: 640506
Applied Workarounds: reset_base_mipmap_level_before_texstorage
Result of abs(i) where i is an integer in vertex shader is wrong: 642227
Applied Workarounds: emulate_abs_int_function
Rewrite texelFetchOffset to texelFetch for Intel Mac: 642605
Applied Workarounds: rewrite_texelfetchoffset_to_texelfetch
Rewrite condition in for and while loops for Intel Mac: 644669
Applied Workarounds: add_and_true_to_loop_condition
Do TexImage2D first before CopyTexImage2D for cube map texture on Intel Mac 10.11: 648197
Applied Workarounds: init_one_cube_map_level_before_copyteximage
Decode and encode before generateMipmap for srgb format textures on macosx: 634519
Applied Workarounds: decode_encode_srgb_for_generatemipmap
Insert statements to reference all members in unused std140/shared blocks on Mac: 618464
Applied Workarounds: use_unused_standard_shared_blocks
Tex(Sub)Image3D performs incorrectly when uploading from unpack buffer with GL_UNPACK_IMAGE_HEIGHT greater than zero on Intel Macs: 654258
Applied Workarounds: unpack_image_height_workaround_with_unpack_buffer
adjust src/dst region if blitting pixels outside read framebuffer on Mac: 644740
Applied Workarounds: adjust_src_dst_region_for_blitframebuffer
Mac driver GL 4.1 requires invariant and centroid to match between shaders: 639760, 641129
Applied Workarounds: remove_invariant_and_centroid_for_essl3
Version Information
Data exported
3/30/2017, 10:36:58 AM
Chrome version
Chrome/56.0.2924.87
Operating system
Mac OS X 10.11.6
Software rendering list version
12.06
Driver bug list version
9.24
ANGLE commit id
a4aaa2de57dc
2D graphics backend
Skia/56 bf2d9e02d58ea01f1c239f7e2fc024cba140ccb1
Command Line Args
Chrome.app/Contents/MacOS/Google Chrome --no-startup-window --flag-switches-begin --flag-switches-end
Driver Information
Initialization time
359
In-process GPU
false
Sandboxed
true
GPU0
VENDOR = 0x8086, DEVICE= 0x162b *ACTIVE*
Optimus
false
AMD switchable
false
Driver vendor
Driver version
10.14.73
Driver date
Pixel shader version
4.10
Vertex shader version
4.10
Max. MSAA samples
8
Machine model name
MacBookPro
Machine model version
12.1
GL_VENDOR
Intel Inc.
GL_RENDERER
Intel(R) Iris(TM) Graphics 6100
GL_VERSION
4.1 INTEL-10.14.73
GL_EXTENSIONS
GL_ARB_blend_func_extended GL_ARB_draw_buffers_blend GL_ARB_draw_indirect GL_ARB_ES2_compatibility GL_ARB_explicit_attrib_location GL_ARB_gpu_shader_fp64 GL_ARB_gpu_shader5 GL_ARB_instanced_arrays GL_ARB_internalformat_query GL_ARB_occlusion_query2 GL_ARB_sample_shading GL_ARB_sampler_objects GL_ARB_separate_shader_objects GL_ARB_shader_bit_encoding GL_ARB_shader_subroutine GL_ARB_shading_language_include GL_ARB_tessellation_shader GL_ARB_texture_buffer_object_rgb32 GL_ARB_texture_cube_map_array GL_ARB_texture_gather GL_ARB_texture_query_lod GL_ARB_texture_rgb10_a2ui GL_ARB_texture_storage GL_ARB_texture_swizzle GL_ARB_timer_query GL_ARB_transform_feedback2 GL_ARB_transform_feedback3 GL_ARB_vertex_attrib_64bit GL_ARB_vertex_type_2_10_10_10_rev GL_ARB_viewport_array GL_EXT_debug_label GL_EXT_debug_marker GL_EXT_framebuffer_multisample_blit_scaled GL_EXT_texture_compression_s3tc GL_EXT_texture_filter_anisotropic GL_EXT_texture_sRGB_decode GL_APPLE_client_storage GL_APPLE_container_object_shareable GL_APPLE_flush_render GL_APPLE_object_purgeable GL_APPLE_rgb_422 GL_APPLE_row_bytes GL_APPLE_texture_range GL_ATI_texture_mirror_once GL_NV_texture_barrier
Disabled Extensions
Window system binding vendor
Window system binding version
Window system binding extensions
Direct rendering
Yes
Reset notification strategy
0x0000
GPU process crash count
0
Compositor Information
Tile Update Mode
Zero-copy
Partial Raster
Enabled
GpuMemoryBuffers Status
ATC
Software only
ATCIA
Software only
DXT1
Software only
DXT5
Software only
ETC1
Software only
R_8
GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
RG_88
Software only
BGR_565
Software only
RGBA_4444
Software only
RGBX_8888
Software only
RGBA_8888
GPU_READ, SCANOUT
BGRX_8888
GPU_READ, SCANOUT
BGRA_8888
GPU_READ, SCANOUT, GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
YVU_420
Software only
YUV_420_BIPLANAR
GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
UYVY_422
GPU_READ_CPU_READ_WRITE, GPU_READ_CPU_READ_WRITE_PERSISTENT
Log Messages
[401:775:0328/171243.039369:ERROR:latency_info.cc(163)] : GpuCommandBufferStub::OnAsyncFlush, LatencyInfo vector size 135 is too big.
[401:775:0329/112839.250582:ERROR:latency_info.cc(163)] : GpuCommandBufferStub::OnAsyncFlush, LatencyInfo vector size 457 is too big.
[401:775:0329/114646.791677:ERROR:latency_info.cc(163)] : GpuCommandBufferStub::OnAsyncFlush, LatencyInfo vector size 114 is too big.
[401:775:0329/131000.479762:ERROR:latency_info.cc(163)] : GpuCommandBufferStub::OnAsyncFlush, LatencyInfo vector size 145 is too big.