This afternoon I was contacted by the operator as, after an ITF unlock, it was not possible any more to close the loop of the B1p_QD1_V galvo.

Before this incident, the corrections were varying typically between -7 and +7V (Fig.1), so the galvo loop seemed to be reasonably tuned (a tuning was done at the last maintenance). The operator mentioned that the SR mirror had to be realigned, and indeed, it seems that the SR mirror was not at its usual position during the failed attempt of closing the B1p_QD1_V loop, so I suspect this is related.

Now the situation seems to have come back to normal after realigning the SR mirror.