The shift started around 1:30  pm after the ITF recover.

Configuration: MICH with BS drift control engaged.

WI CH ON at different powers to minimize the contrast defect.

11.27 UTC-> CH ON P=100 mW.

12.41 UTC-> CH ON P=200mW

13.46-> CH OFF

Effect on the contrast defect is clearly visibile. As expected, the plateau is reached after about 1 hr (see attached figure).

Following the indication found in 37816, analysis of B1p camera images is in progress.