Last Tuesday (Aug 21, 2023) Rick and I went down to the EX station while the IFO was still locked. 
We asked the operator to turn off BRS sensor correction (Sitemap-> ISI_CONFIG ->SEI_CONF ->WINDY_NO_BRSX). This was to allow us to gentley walk to the other side of the beam tube to access the PCAL Transmitter module.

Once there Rick and I opened the Tx enclosure and blocked the Outer ( Lower ) PCAL beam at GPStime: 1376752360
We saw the following motion of the PCAL channel :  H1:CAL-CS_TDEP_PCAL_X_OVER_Y_REL_MAG .
We did expect this to go up and then settle down. We were suprised by how long it took to settle down.
At GPStime 1376753100 we blocked the inner (Upper) beam was blocked.
That seems to last uninteruppted until GPStime: 1376754170

At 1376754420 ISC_LOCK went to from NOMINAL_LOW_NOISE to DOWN and signals the the start of the End station measurments made that day.

More analysis coming soon.