Zyxel LTE 2566 randomly restarts itself

Hello everybody,

I've bought myself an LTE modem Zyxel LTE 2566 and it randomly restarts itself. I've been having it for a month and it randomly restarts 0-3 times a day, but I use it only for like 5 hours every day.

Yesterday I got a different device of the same Zyxel LTE 2566 model and today it restarted itself too, twice already, 5 minutes between the restarts.

I do have almost factory settings, I've changed only SSID, password, and disabled 2.4 GHz Wifi since I am using only 5 GHz.

The firmware is the latest.

Do you have any experience with this or any advice? The modem is not much cheap and having it restart itself multiple times a day is super annoying, especially during the meetings.