There seem to maybe be lines in DARM that I don't recall from the past, so we're looking in to a few of those.
The line at 843 Hz seems to be created in the calibration process, since it is present in GDS-CALIB_STRAIN, but not present in CAL-DELTAL_EXTERNAL. Probably not a problem (unless it's there in NLN), but worth noting that it is *not* related to locking problems, since it's not in the raw DARM data.
Jenne asked me to check a line around 27 Hz, this does show up in max power (today see brown trace) but also was there in max power before maintenance Tuesday this week (pink trace).
It doesn't seem to really show up in the NLN state (red trace is before maintenance, blue is one of our locks from early this morning).
My conclusion from Jennie's plot is that that 27 Hz mode isn't a major cause for concern; it's not something new that's giving us trouble.