I measured the OLTF of ALS CARM loop when both PLLX and PLLY gains are reduced by 6dB (-26dB and -29 dB for PLLX and PLLY, respectively) and CARM IN2 gain is increased by 3dB (23dB).
Figure 1 shows the comparison of original condition (thin line in fig1) and above condition (thick line in fig1).

Though the situation becomes much better, it is still worse than before (klog32464).
By changing the PLLX and PLLY gain, the bump stracture can be changed, so the bump seems to come from PLL loops.
Further investigation of PLL loop is necessary.