Hello!
RB 2011 now and 951 before.
Several times a day the USB-modem is disconnected. In the log message “lte 1 link down.” Then immediately connect back.
The ZTE modem is connected through an active USB-hub. The modem has an uptime of several weeks.
The most surprising is that almost disconnections occur at different times, but some have a system of intervals:
05:11:47 - 05:11:53 (every day!)
13:14:27 - 13:14:47 (15 to 25 days per month)
Firmware 6.40.4.