I upgraded RouterOS and the LTE firmware in the same period. Now, my LTE connection constantly drops down and then never comes back unless I do something to the LTE settings (like flipping 3G or Roaming and applying). This occurs one or 2 times a day I would say.
I suspect this is the firmware (version EG12EAPAR01A11M4G).
Is there a way to downgrade just for a test?
A bit worse here - LTE interface has disappeared completely. Appears back randomly only after juggling various firmware upgrades/downgrades to previous version, some beta version, netinstalls and so on. But after restart interface is gone again. Anyway most of time no LTE configuration changes possible since no interface 
. Log full of “lte1: reply timeout for: AT E0 V1”.
Jira ticket SUP-85617 was raised yesterday - waiting for support. Hopefully they can help me soon.
Hi. Just wanting to know if there was any outcome/resolution to this issue? I only randomly get the LTE interface back after many reboots but then disappears if the device reboots for any reason.
Have you upgraded to the latest modem firmware?