Abnormal TCH assignment failure ll E******* ll 2g

[beniy]

Hello E******* Experts,
I have 10 worst cells in all my network that they have abnormal TCH assignment failure.
The reason that I call it abnormal is as below:

When traffic is near to 60% TCH assignment success rate is near 99%, but when traffic goes high and it reached to more than 90% suddenly TCH_ASS_SR is decreasing to 60%

I think there is one feature that is not working properly.

E******* ll G10 B ll 12 TRXs in site level ll 1 E1 ll comfact 2 ll Abis Mode : Flex

I will appretiate if you support me in this case that seriously this is annoying me.
In advance thanks and rep to all your answers and your kind support.
BR,
Beniy