I have just gotten the new purple sim card this week and when I installed it into my phone it just kept restarting the phone. I got the texts saying everything's set up, it seems to receive texts and calls just fine but every 5 minutes the phone will restart.
It is an older phone. A Samsung gt-c3590 flip phone. But it is 100% the sim card doing it, I have removed the card and it stops restarting.
Oh and a roaming data icon has appeared when I installed the sim despite roaming data being turned off.