This is correct. In the Account window, look for that red-highlighted row; indicates that you'll be in a margin deficit post-expiry, which IB won't let happen, so they'll liquidate positions (even long ITM ones) to avoid it. Surprised to hear it's happened as early as 2pm EST though? Maybe I've just gotten lucky, since I've definitely let that red row hang out there for a while on expiry day, thinking I had until 3:30pm before liquidations would commence (which I thought was the case for some reason...) Good luck trying to get any definitive info from IB on their liquidations process. They won't tell you anything -- just that they have a super-secret proprietary algorithm that they can't tell you about, other than your best bet to not get screwed is to avoid getting too close to a margin deficit after which all bets are off.
IB are sweethearts compared to Fidelity! I had 50 ADSK Calls I bought for $.40 and they went to $3 around 1EST. The assholes sent my order as a market order while I was on the phone with Margin to ask when they sell. They said 2PM or 2:30. I put in. order at $3.90 and they cancelled and hit the bid $2x$3.90 I got filled at 35 @$2 and 15 sold at my offer when stock was $4 ITM. Happen years ago, I hate them!
Yeah I was hoping to bleed off a couple more dollars from some ITM short SPY calls. It was a spread so I was never in danger of getting a late-day smack down. They are super liquid so I was going to hang on right to the end before I closed 'em out... Nope. I blinked and they were gone. Really didn't lose anything, but it was surprising.