Your ISP is known not to be super P2P friendly.
So I wonder if it is also related. They will know if you are a heavy user & what type of bandwidth you are using. So watch your back.

Here's an example of how a p2p bandwidth shaper can work against Gnutella: Bandwidth Shaper Sample - typical of how some ISP's use it (click on link) ie: giving priority to net surfing & low priorities to p2p sharing