I looked at the frames to try to understand the reason for the drop of the intensity in the HWS images.

Figure 1 shows the trend of the maximum intensity on the CCD as a function of time (from 23:08 UTC).

The first drop seems to be rather well time-correlated to the tilt of some of the recycling cavity optics, at the time of the onlock (fig. 2).

The final drop is concident with the large displacement occurred to the SR, around 3:21 UTC.

This excludes any issue with the SLED source.