Steps to reproduce the problem:
1. Go to https://jsfiddle.net/fqoahvqo/ on a Samsung S6 or S9 (these are the only devices I've seen this issue on so far)
2. SMPTE Color Bar video should start playing
3. Keep hitting the "Run" button on the top left (or refresh the page) until you see the video fail to load (bottom right screen will stay black).

I see a fail rate of about 1/5 times on these devices, but it seems to vary.

What is the expected behavior?
Video should play correctly when using Media Source Extensions

What went wrong?
Not sure. This works 100% correctly on a Pixel XL and Moto Z (and OSX/Windows Chrome).

Did this work before? Yes Unsure

Does this work in other browsers? Yes

Chrome version: 66.0.3359.126  Channel: n/a
OS Version: 10.0
Flash Version: 

This test video forces "Low Delay" mode so it's possible it's related to that. When the video plays correctly, Media Internals looks like:

debug				Video rendering in low delay mode.
duration			unknown
found_video_stream		true
frame_title			
frame_url			http://fiddle.jshell.net/_display/
height				1024
info				Selected GpuVideoDecoder for video decoding, config: codec: h264 format: 1 profile: h264 high coded size: [1024,1024] visible rect: [0,0,1024,1024] natural size: [2048,1024] has extra data? false encrypted? false rotation: 0°
origin_url			http://fiddle.jshell.net/
pipeline_buffering_state	BUFFERING_HAVE_ENOUGH
pipeline_state			kSuspended
player_id			4
render_id			17
seek_target			42
url				blob:http://fiddle.jshell.net/47aacc34-7baf-453f-894c-078edf87e10a
video_buffering_state		BUFFERING_HAVE_NOTHING
video_codec_name		h264
video_dds			false
video_decoder			GpuVideoDecoder
width				2048

And when it breaks (notice the lack of width/height):

debug				Video rendering in low delay mode.
duration			unknown
found_video_stream		true
frame_title	
frame_url			http://fiddle.jshell.net/_display/
info				Selected GpuVideoDecoder for video decoding, config: codec: h264 format: 1 profile: h264 high coded size: [1024,1024] visible rect: [0,0,1024,1024] natural size: [2048,1024] has extra data? false encrypted? false rotation: 0°
origin_url			http://fiddle.jshell.net/
pipeline_state			kPlaying
player_id			48
render_id			3
seek_target			1
url				blob:http://fiddle.jshell.net/f87bed89-1fe4-4e64-9eb1-cf2705445699
video_codec_name		h264
video_dds			false
video_decoder			GpuVideoDecoder