I tweeked ETMX and ETMY yaw DoFs manually to find the good alignment of arm.
Though we can increase the transmission power slightly, there is still sudden arm transmission drops.
In addition, there are several types of drops: GRY drops at the same time and GRX drops at the same time.
So, it seems that the issue is not coming from one suspensions but several suspensions.
Since ADS for yaw DoFs are not working well (klog24479), I manually tweeked ETMs to find the good alignment of arms.
When I tweeked suspensions by 0.5 urad or so, transmission light power seems slightly better but it is difficult to confirm it because of the large fractuation of transmission power.
Also, it is difficult to tweek two DoFs at the same time, so it is necesary to close ASC (WFS at REFL) at least common DoFs (of course both Com/Diff controls are better).
After that, I tried to find which suspension causes the transmission power drops.
Figure 1 shows an example of Type-A yaw error/feedback signals and Transmission light powers.
Cursor shows the timeing when dropping started and recovered.
It seems that IRX, IRY, and GRX drop happened at the same time while GRY also drops slightly but timing was different.
I'm not so sure but if GRY drop is just an acidential one, this events implies that ITMX, ETMX, or PR3 cause the drop because GRX should be independent from the other suspensions.
Figure 2 shows an another example of their time series data.
In this case, IRX, IRY, and GRY drop happened at the same time while GRX didn't have the drop.
This implies that ITMY or ETMY causes the drop because GRY is only affected by ITMY, ETMY, or SR3 but SR3 should not affect IR transmission power.
So, at lease these two events have a different origin.
It is better to see more details of each events during silent run (klog24475).