Help? Sleep/Wait Bug

[RIP Hank the Chicken 2015-2015]

The game was running fine for maybe 10 hours. Then I started having a bug that I can only sleep or wait for an hour or two at a time, and then the sleep or wait is interrupted. The screen shows "-1" for a split second when sleep or wait is interrupted. I tried dismissing followers, which didn't help. Possibly related, NPCs were acting alerted when there were no enemies nearby (i.e., inside the Brotherhood of Steel base). Any ideas? Thank you.