I'm thinking the OP might be just a casual user of WInscp, like myself, I'm not really interested in making a log,and posting it, and finding out what protocols i'm using. To me the most helpful answer would be either "Yes it's a bug", or "Nope it works on my computer". Since an admin answered the question, that should be easy to make that determination. If I know it's a bug I have no further worries. If it is my computer I can choose to work around the bug, or spend a long time trying to pinpoint the problem. For the occasional time I might have to cancel a big file update, ctrl-alt-delete is a lot faster than logging everything and posting.
Anyway for me, cancelling a big file upload does hang the program. Win 7, ftp with explicit encryption, I post this bc it helps other users know that the problem exists, if they encounter it.