CSSR & DROP degradation

Hi Team,
Any one have any suggestion or feedback about WCDMA CSSR & CDR degradation because of RRC and RAB failures due to AC fail in Nokia. 3-4 sites affected in same vicinity after swap from H-N.
AC parameters are fine. Further in RAB failures it is due to DL PWR failure.
NO availability issue. DL power utilization <=70%. Power parameters are aligned.
NBRs are aligned.

Please suggest any check.