At the time of file generation, the router was successfully connected to the mobile operator and had data connection established, but the connection is established only 15 minutes after boot, which is not normal. The file itself contains events from 20 minutes of router's uptime only. A file from several hours of device operation would be more informative.
However, within the captured timeframe there seems to be issues with the CPU retrieving data from the modem, thus restarting it at a certain point. This would indicate either hardware or firmware issues.
Considering that the firmware version of the internal modem is quite dated, I would suggest to try performing an update.
I will send you the instructions in a private message.