Could be a bug of the rom. I know it's probably difficult to get stable non stock based roms for your phone. You might want to check with the developers of the rom to see if there's preferred settings or another modem to use that might work better with it.
Need some help, advice, something fixed? Hit me up on Hangouts @ es0tericcha0s and check out my site: http://mobilemojo5280.com
for more info!
HTC Droid Eris / Motorola Droid / Samsung Galaxy S Fascinate / Motorola Droid X / LG G2x / HTC Evo 3D (x2) / Samsung Epic 4G Touch (Sprint S2) / HTC Amaze / Samsung Galaxy S3 (International) / Samsung Galaxy Note 2 / Nexus 4 / HTC One / Samsung Galaxy S4 / Sony Xperia ZL / Nexus 5 / ? (One+1 maybe...)