While following up some hVeto results, I came across some very strange signal in ISI-HAM4_BLND_GS13Y. It's also in X and Z - I haven't checked other degrees of freedom or the raw GS13 signals. For several days, there's a sweep from ~700 Hz to 1024 (Nyquist) once per second. It doesn't seem to be quite aligned with the second. The first plot is an Omega scan that shows what it looks like.

The second plot shows the onset at June 9 16:49:54 UTC. The only thing I can find in the log is a restart of h1susb123 at 11:50 local (alog). I think this channel is SEI not SUS but maybe they share a front-end machine? The problem looks to be continuous until about June 13 21:30 UTC, third plot. I don't know what fixed it. There's more digging in we can do if needed. This is not a huge problem for detchar, the sudden change in the channel just caused some weird results in hVeto. We probably should be ignoring the high-frequency part of the signal anyway.