Mr Faber,
Do you think I have a crystal ball here?

If your backtrace was not meaningfull, how do you think I "guessed" you changed priority by hand?

Actually, the backtrace is not the most important part of your message, but this is the key:
22:02:48: Debug: DownloadQueue.cpp(795): assert "0" failed.
That is why every information is important.
I think the answer is yes, you found another bug

GonoszTopi, can you take a look at that? Seems like we receive a wrong tag from amuleweb when we change priority.