Default [Q] i9305 mobile data problem on new carrier

Hi guys,

Last week I loaded the latest SOKP rom to try on my i9305, it's a great ROM and I wouldnt like to change.I had to change carriers a couple of days ago and have had issues since then.

Firstly the signal indicator on LTE was constantly going up and down in multiple good reception zones - so I tried some different modem files and found XXUEMKC works well. Now after LTE is connected for a few hours, especially idling, the signal indicator goes orange and no data flows, I need to turn off data and turn it back on to make it work again.

Any ideas?