Hi Gprastomo,

The IRAT in PS is normally done during the CM mode and it is somehow non continuous unless there is a feature installed that permit the system to HO from HS to GSM. Normally when you have irat failure it can be the 2G system is congested due to lack of TCH for data session due to high CS traffic. Kindly ask your 2G RF counterpart to check the accessibility in the RF side in terms of data traffic.

In case they find some congestion then the problem is in the RF.

Br,
Sen