PS and CS CE congestion increased, but no increase in traffic

I have an increase in PS and CS CE congestion both in UL and DL.
But there is no increase in traffic.
What causes this?
Vendor Huawei

Did you check board level stats?

Dsp BBPTC

Traffic is within capacity.

How many UMTS cells config on this site?

6 cells configured.

Normally UL CE congestion increases but DL congestion increase suspects to Hardware issue.

CE congestion Failures observed on one site?

All 6 carrier have increase the CE congestion?

What is CE Utilization?
If its higher than 70% go for board enhancement, if its low check spft license and board exact CE numbers, if soft license is less than board actual CEs, than increase it.
Your UE or Attempts increased may be.
You can reduce the reserved codes, or tune LDR thresholds.
Wich will consume less CE.

Update: I have found It was due to license distribution issue due to time misalignment between NEs.