Still works with OpenCL disabled. Yes, updating Windows to 20H2 seems to have corrected whatever the underlying problem was. I assume that the offending files were replaced by the update.
It is possible that .NET was the problem. It was also updated. I suspect this because of the immediate crash when clicking the TGA tab. I'm thinking that there was something about a widget used for the popup which should have been displayed.
btw: I'm very impressed by the responsiveness of your team. You are all fantastic. In my mind Serif and Affinity wins!