This is what the latest comment on the git issue says
Using Beta 114, I confirmed that setting dom.ipc.processPrelaunch.lowmem_mb to 0 MB fixes this issue which seems to happen when there’s a memory pressure in the system. I can provide a profile with and without this preference if requested. I don’t fully understand how this preference affects memory management when dom.ipc.processPrelaunch.enabled is false. Yet somehow it does.
Does this help at all?
I really wish I were multilingual for this exact reason