Over recent days, we've been noticing that the ISS diffracted power has been changing more than usual, which has been varying the input IFO power by ~0.5W lock to lock. I adjusted the ISS RefSignal Friday night to mitigate this, but it still seems to be moving around.

I've attached trends of this drift over the past week and month (I include some temperatures because they've been on our minds recently). The ISS first appears to start doing strange things back on May 16th (cursor location in the ndscope screenshot), which lines up with when Jason did an FSS aligment tune-up and the RF distribution went down due to ongoing power supply work, which unlocked the PMC and RefCav while Jason was in the enclosure, but the ISS itself was not touched other than turning the autolocker on and off. Two weeks after that, the diffracted power seems to settle.