Well after you quit your torrent client, your ip is still on the tracker for a period of time. Not to mention, it is also on other clients who have connected to you and they might spread it out through peer exchange and DHT mechanisms. So what you're experiencing is totally normal.
It's weird that you can't go to the router page with only 50 connection, what is your upload/download speed in your client and what is your line bandwidth? I'm fine over here with 250 connections. The router actually has to keep track more than you set as it will let closed connection stayed in your router for some time.
P.S.: utorrent is lean and nicer IMO, but it has nothing to do with this problem.