I checked the REFL RF signals when PRM was aligned (fig1).

According to klog27900, f1 and f3 are generated in the same EOM (EOM3), and f2 and f_IMC are generated in the same EOM (EOM1).
Though temperature change observed with PT04 was less than 0.01 K, trend of demodulated signals of f1, f2, f3 sidebands seems correlated with the temperture change.
Power change might be observed even in DC power on PDA1,3, and 4 but the ratio of changes and DC power seems much less than RF AM drift rate.

All RF signals have similar bumps around T cursors in fig1, though RF45 and the others are generated at the different EOM.
So, RF AM source seems common one for both EOMs like temperature change though temperature change around T cursors are not clearly seen.