RUT950 keeps disconnecting, despite 4G presence

The RUT360 is in the same area and uses a duplicate sim off the same contract. See mobile stats in the screenshot:

Firmware Versions:

RUT360:
Firmware version: 07.04.5
Internal modem firmware: EG06ELAR04A04M4G

RUT950 (1):
Firmware version: 07.04.5
Internal modem firmware: EC25ECGAR06A04M1G_01.004.01.004

RUT950 (2):
Firmware version: 07.04.5
Internal modem firmware: EC25ECGAR06A04M1G_01.004.01.004