I've hit the following crash signature four times in just a few minutes. The STR involve opening or closing a YouTube page in new background tab (by Cmd+clicking a YouTube link).

I have fission.autostart, gfx.webrender.all, and gfx.webrender.software all set to true, but I haven't been able to diagnose which prefs are required.

bp-1ec1f9e5-0309-4ae6-8c62-ba5d70200720
bp-46eb3302-b58b-4e82-9678-e774a0200720
bp-9e21d07b-734b-4335-8540-b422a0200720
bp-eafa0e9b-bf1a-4161-9899-a67fc0200720

Top 10 frames of crashing thread:

0 XUL composite_TEXTURE_RECT_YUV_frag::sample_yuv x86_64-apple-darwin/release/build/swgl-336b1985b8fc45c0/out/composite_TEXTURE_RECT_YUV.h:253
1 XUL composite_TEXTURE_RECT_YUV_frag::run x86_64-apple-darwin/release/build/swgl-336b1985b8fc45c0/out/composite_TEXTURE_RECT_YUV.h:331
2 XUL void draw_quad_spans<unsigned int> gfx/wr/swgl/src/program.h:139
3 XUL draw_quad gfx/wr/swgl/src/gl.cc:3602
4 XUL DrawElementsInstanced gfx/wr/swgl/src/gl.cc:3722
5 XUL webrender::renderer::Renderer::draw_instanced_batch gfx/wr/webrender/src/device/gl.rs:3374
6 XUL webrender::renderer::Renderer::draw_frame gfx/wr/webrender/src/renderer.rs:4732
7 XUL webrender::renderer::Renderer::render_impl gfx/wr/webrender/src/renderer.rs:3511
8 XUL webrender::renderer::Renderer::render gfx/wr/webrender/src/renderer.rs:3255
9 XUL wr_renderer_render gfx/webrender_bindings/src/bindings.rs:606