Anyone who has seen this before?:

[-1210947904]BACKEND[0]: fd 40 has revents 0x00000008, but hasn't been handled.

It happens rather sporadically in a Roxen production server (the same one we just upgraded to bleeding edge Pike); in fact, it's the first time I see it. The server appears to hang at that point, so my watchdog script (external) kills the server and restarts it after that.