Shiela showed me that PR3 alignment in Pitch is different for in vs out of lock, and it's about 1.5urad.

I've been looking at other optics, and today found that PR2 Pitch also has two distinct alignments of in vs out of lock.

Attached is a trend of PR2 during ER7, pitch on the bottom plot, that shows the two states.

The trend of PR3 pitch is essentially PR2 pitch inverted, however due to techincal dificulties, the plot is forthcoming.