New Call delay bug


Jan 24, 2017
In weekly rom bug that i have (even when i do factory install) there is anoying outgoing call delay bug. I have a friend and he have global rom (im think its note 9) and im on weekly eu rom (mi 10). His device when u hit call button instanly switch 4g or 4g+ to 3g or even 2g. On my phone he wait 4-7sec then he switch network to 3-2g and start to making calls. I google it i try some solutions but nothing help. Does anyone have any idea about it? I switch sim cards and my sim work great on friends global rom. I try to change bands 1by 1 and all combinations with lte nothing help.