These are the FSR scans done yesterday. As mentioned by Fabio these were interrupted from time to time. Could experts check what was the problem with the green?

We took a look at the unlocks of the green during the scans.
They seem to be triggered by an oscillation at around 56 kHz that suddenly appears on the error signal (see figure 1)
By taking a look at the spectrum and the fft time of the unlocks we can spot several lines (figure 2 and figure 3).
The 70 kHz line is the phase modualtion used to lock the arms.
There are two fixed lines at 13.8 kHz and 27.6 kHz. They might be generated by the beating between the 70 kHz and the 56 kHz.... or the countrary. 
We can also spot a line at around 6 kHz which is increasing in frequency. It seems that there is a beating between this line and 50 kHz (see figure 4)

We do not have clear explanations for those oscillations yet (fixed and wandering), could they be due to some mechanical mode of the WE mirror?

We quickly look an other unlock which shows a similar but different behavior (figure 5)