I run bitcoind headless on a linux box with maxconnections=256 and port 8333 open on the router. Using Bitcoin Node Manager I monitor node status occasionally. Peer count of course starts at 8 and slowly, over the course of three or four weeks, ramps up to 150 or so. Roughly every month or so the number of node drops precipitously to less than 20, then starts climbing again. I can verify via the logs that bitcoind did not restart and that my network did not go down. I have a second node that runs solely over TOR and while it does not have an many peer connections, its peer count doesn't fluctuate in this way.

1. Does anyone else notice this?

2. Any ideas what might cause this?

3. Any tips on how (or even if) I should troubleshoot this? (i.e. things to look for in the logs)