Is that time stamp really correct? I wanted to look at the signal closely to see if I could get any feeling for why it would look so different when positive vs. negative, but I do not see a triangle anywhere near this time (1023780144)...
Interesting. It seems for me that there is a dependence of the noisiness as the beat frequency is scanned.
As you increase (or decrease?) the offset, C1:ALS-BEATY-COARSE_I_IN1 becomes bigger and more crisp.
The resulting out-of-loop stability also seems to be improved as you can see from the crispness of the PDH signal.
Do you find why this happens? Is this because the beat S/N depends on the beat frequency due to the PD noise?