Yes, I got bought in on MA by IB this morning. The notices they sent me didn't make sense, saying they couldn't come up with the shares for settlement when I've held the position for weeks. I've tried to ask them when this happened in the past how settlement could be a problem on a position I've held for over a month, but I just get doublespeak. If the shares are no longer available that's one thing, but that's not what the notices say.
I've had about 7 possible buy-in notices from IB in the past few months, but this is the first time they actually did it.
I re-took the position in my Ameritrade account, I'll see if that works better.