BR1_PRO_5GN "disconnected in SIM slot" every 2 hours

Hi all!!

We have 3 Peplink BR1_Pro_5G in 3 different locations. All 3 devices have a sim COSMOTE card. The 2 of them are 5GD and the last is a 5GN.

The last BR1 that we have purchased has issues. Every 2 hours, it disconnects for about 10 seconds and then reconnects.

At first, we thought that the cosmote has problems. So, we replace the 5GN with a BR1_PRO_5GD device for testing using the same sim in the same physical place (with the same configuration). No disconnection occurs. We also tested this using a different service provider (VODAFONE).

We have noticed that the cellular firmware in the defective device is different from that of the other devices.

When we try to upgrade the cellular firmware, it says that no update is available.

How we can solve the problem with the disconnections?

Thank you very much!