Gustav_ASUSTried all these methods in past few days.. but no change... Same as mentioned, but when i was using mobile data on 2nd sim i had really bad experience... I mean network bars were fluctuating.. speed was fluctuating way more.
You can start troubleshooting this problem by:
1) Switching places of the two SIM cards and see if that solves your problem.
2) Disable cellular data and phone calls on one of the SIM cards.
3) If you have a third SIM card at hand (or can borrow one), try switching your current SIM cards to that one.