Don't have any answer for you on this one. As the message actually suggest, you might consider not watching those threads. The traffic is so slow on this forum, it isn't as though manually watching threads is a chore.
Still, I'm curious what set these off (this might have been better in the Q&A forum). There has been a lot of spam of late (bots are getting smarter), and perhaps this has something to do with it, but I have no clue.
Either way its pretty annoying. Since I don't personally watch any threads here, I can't tell you if anyone is having any similar problems.