I'm running into this same issue! This never happened before, but I believe it started recently with an update I took this year - I don't take every update so it's somewhat difficult to track, but I'm pretty sure it was with an update that was released in the past month or two. Then I think there was one more subsequent bugfix release, but ever since those last two releases, I've had issues where winscp will just be kinda frozen - menus will open, but they don't do anything. I can't exit out and I have to force quit with the task manager.
This happens every morning and it's pretty annoying. I thought it only happened when I suspended or hibernated, but last night I didn't turn off my computer and this morning it was frozen again.
Please let me know what information I can provide (logs?) to help debug this issue.