Nothing Rendered (Firefox 134.0.2)

I'm using Speedscope to profile a small C# program (collected & converted by `dotnet-trace`), and it seems to load in Speedscope. But nothing ever renders (except some tooltips when I hover over invisible boxes). There's a bunch of failing asserts in the console, it looks like the custom framebuffer is incomplete:
```
Uncaught Error: Assertion failed.
H graphics.ts:34
get framebuffer graphics.ts:1379
_updateRenderTargetAndViewport graphics.ts:574
clear graphics.ts:501
onBeforeFrame canvas-context.ts:60
requestFrame canvas-context.ts:53
renderCanvas flamechart-pan-zoom-view.tsx:526
onMouseLeave flamechart-pan-zoom-view.tsx:691
Ca Preact
graphics.ts:34:26
H graphics.ts:34
get framebuffer graphics.ts:1379
_updateRenderTargetAndViewport graphics.ts:574
clear graphics.ts:501
onBeforeFrame canvas-context.ts:60
(Async: FrameRequestCallback)
requestFrame canvas-context.ts:53
renderCanvas flamechart-pan-zoom-view.tsx:526
onMouseLeave flamechart-pan-zoom-view.tsx:691
Ca Preact
```

I can upload the JSON if needed, but it doesn't seem to be related to the specific trace file. My internet is pretty slow right now (~20KiB/s) so I'm trying to avoid any uploads over a few hundred KB.