OnCall
ISC at 09:00 UTC for the worsening of the sensitivity.

I am really puzzled about why the ISC on-call should be a priori responsible for the sensitivity of the whole interferometer (this has happened also another time with the ISC section of the DMS completely green, by the way); DetChar shifters should be the first responders about changes in the performance of the detector, in my opinion.

DMS
ISC - ASC_BS_TX_INPUT and LSC_B4_112MHz_MAG red sub flags. Expert informed.

The ASC_BS_T*_INPUT flags are expected to be red (or yellow at the very least) since the BS loop is left in Drift Control mode; occasionally, also the COMMp_TX_INPUT flag becomes yellow, but this is more related to the weather conditions. The B4_112MHz_MAG flag may be red in consequence of the BS loop, but it seems too much a big effect to me. Other possibilities could be again the weather or some mistuning of the B4_56MHz demodulation phase (the B4_56MHz_DPHI flag being yellow): this has been wandering all the time, but usually quite closely around zero; for example, another "yellow" period is around Apr 14th (see Figure) which, however, did not cause any misbehaviour of the ITF. This will be kept under observation and the hard-coded offset will be changed if needed, as it happened just before the start of O3.

Pending
After the disabled the full bandwidth loop of the BS of Bersanetti ITF is more stable but noisy, If Bersanetti will restore standard condition, contact Nardecchia to set WI_TCS CO2Laser set point (Set Adjustment for 10 minutes).

Given the strong dependence of the sidebands (and the alignment working point) from the tuning of the TCS, I would rather fix the TCS first, as the action seems to be self-contained while on the contrary the BS loop may depend on this. I will contact Ilaria and the Commissioning Coordinator and devise the best strategy to tackle the issue.