I checked the IOT2 tables for scattered light. The beam on IOT2R was hitting an optic mount, so I blocked it. However, the beam was reflected from the black glass dump on the top mirror so it was already small. I also checked the tables by shaking them and got no coupling. I shook the output arm vacuum enclosure, no evident coupling. I shook several HAMs. Shaking HAM2 seemed to significantly increase the jitter peaks, periscope and HPO, while shaking HAM 3 did not. This may suggest clipping on HAM2. Ill look into this more in the morning.