Same here -- happened on 3 itineraries in the past week. I put an EF watch on my seats from now on. Sure enough, my phone blinged in the middle of the night with a text from EP to show my husband bumped out of the bulkhead seat next to me. Immediatley called UA and was told that seat is now blocked, maybe by an air marshal. You're kidding. Thankfully there were 2 exit seat rows still available. This is really annoying.