That tells us the shell* is getting stuck when we ask it for the video's thumbnail. (*Or something that the shell is asking, in turn. e.g. It could be a video splitter/codec that the shell depends on for the type of video data or container.)
I'm not sure why it would work in File Explorer but not in Opus, since it's basically the same mechanism being used in each (in this situation).
You could try generating a process dump and sending it to us. See Manually generated logs in Automatic crash logs (for bug reports) for how to do that. Make the logs while the freeze is happening.
Based on that we might be able to see where things are stuck, or at least what is stuck. It might identify the splitter/codec that's causing problems, which may just need updating. Or maybe Opus is doing something wrong. The log will tell us.