I'm doing some debugging on a pixel and noticed some errors written to the console. Specifically:

[15700:15700:0119/104016.368147:ERROR:gles2_cmd_decoder.cc(18268)] [.DisplayCompositor-0x3774c2186000]GL ERROR :GL_INVALID_OPERATION : glCreateAndConsumeTextureCHROMIUM: invalid mailbox name
[15700:15700:0119/104016.368433:ERROR:gles2_cmd_decoder.cc(10094)] [.DisplayCompositor-0x3774c2186000]RENDER WARNING: texture bound to texture unit 0 is not renderable. It maybe non-power-of-2 and have incompatible texture filtering.
[15700:15700:0119/104016.551494:ERROR:gles2_cmd_decoder.cc(10094)] [.DisplayCompositor-0x3774c2186000]RENDER WARNING: texture bound to texture unit 0 is not renderable. It maybe non-power-of-2 and have incompatible texture filtering.

It's pretty easy to repro this on device. Create a window, load a page and while the page is loading close the window. I was using slashdot. I thought this might be related to --mus, but I can repro without that. This is a tip of tree build e8a2a53e560aec5b1316da12dc10065bdafc7aad with R65-10309.0.0 as the base image.