Never had any filters. It seems to be literally filtering out "random" emails (seems to be every 2nd one, at least last night).
Just got 2 emails from someone, and only 1 was delivered to my BB.
I did the "full" setup for BIS (enter wrong password, select "enter settings manually", etc.) because that was the only way I could set up IMAP.
If I just put in username and password, I got POP3. That seems contrary to what others have reported here.. I've heard people say they enter username/password and get IMAP but that doesn't work for me.
Should I try deleting/recreating the BIS account? Not sure why this started happening all of the sudden late last week (ie. around the time RIM announced this outage).