Started seeing it with 2.9.46, went to .50 and had the same. Dropped back to .48, more of the same.
We regularly see events like this...

which, oddly enough, all the clients stay connected (I haven't tested client performance during the event) but the WDS dies until I manually take the radio down and put it back up, completely opposite to what winbox shows.
It will happen completely erratically. Sometimes its once every 5 minutes, sometimes it can go more than a day without failure.
Heres the site running normally. When its not freaking out, it actually performs quite well...

I dunno, I'm starting to lose patience with it. Any ideas?