Abstract:
I realigned PR3, ITMX, and ETMX for finding GRX flash.
GRX flash is recovered!!

Detail:
First, I slightly tweeked PR3 to roughly maximize TRX PD signal.
Then, I tweeked ITMX and ETMX with the same manner as klog18917 and find the good alignment.

Alignment changes are as follows:
PR3: (P,Y) = (-101.0, 67.5) -> (-100, 70.5)
ITMX: (P,Y) = (0.0, 5.5) -> (1.0, 26.8)
ETMX: (P,Y) = (0.3, -40.0) -> (2.0, -25.4)

Figure 1 shows the OpLev signals and TMS-X PD output.
As you can see, GRX constantly flashes now.

Note:
Good values of ITMX and ETMX yaw are largely changed compared to the others.
It might be because the longitudinal positions of ITMX and ETMX are changed due to heat link connection, which can change te good values of yaw because of L2P coupling.