The docs for CtxRef prominently mention that it's an Arc and that it's cloneable. But starting a new frame mutates, not the context, but the CtxRef, invalidating prior clones. I'm sure there's a good reason for this, but in most libraries that give cloneable "handle" types (eg winit, wgpu, etc), mutating methods only affect the thing the handle points to, not the handle itself. I think the API and docs shouldn't suggest that CtxRef and Context are handles, or at least mention that they're handles only for the duration of one frame.