I'm using BT4R1 (haven't done a complete upgrade, yet). Seems like if I use wicd to connect to my WPA network, the connection randomly resets. I've looked through google and the logs, but haven't found a smoking gun yet for the cause. Switching to use wpa_supplicant and dhclient manually clears up the issue (but I figured I'd let you know). I'll upgrade to BT4R2 this weekend and see if that fixes the issue as well.
Regardless, this only started happening recently. I do an apt-get update && apt-get upgrade daily (but not a dist-upgrade, to keep myself on BT4R1). Perhaps I'm doing something wrong with this action?