Enabling SDL logging allowed me to track down this error.

This line creates a texture and takes ownership, but SDL will sometimes destroy the texture owned by this object, causing SDL_DestroyTexture to fail later and sometimes crash the program.

This issue can crash the samples if you restart the renderer during that program.

I'm noting this now so that I don't forget to fix this. I'll probably have the renderer track its textures with weak references and release ownership of its them when the renderer itself is deleted.