At around 14.00 UTC, some jumps started to appear in the main ITF signals (see fig.1). Assuming that the jumps could be related to some higher-order mode, Michal suggested to change the ETM RH settings to move the cavity away from this critical region. 

Before starting the tuning of the ETM RHs, the configuration was:

NE: V = 18.3 V (9.02 W)
RoC_NE = 1669.6 m

WE: V = 19.1 V (9.80 W)
RoC_WE = 1670.5 m

A pure differential change was therefore applied, with the goal of changing the RoCs by:

RoC_NE: -2 m
RoC_WE: +2 m

At 15:09 UTC, the RH settings were changed to:

NE: 9.02 W (18.3 V) → 9.82 W (19.1 V)

WE: 9.00 W (18.3 V)

Later, Piernicola and Mattia realized that the jumps were actually related to the diagonalization. After disabling it, the jumps disappeared).

At 16:25 UTC, the ITF unlocked due to a glitch.

From this point onward, the ISC team worked on the lock acquisition automation.

The effect of the step will need to be evaluated during the next locks.