USB LTE key issue

I’m experiencing a problem with my Vodafone LTE USB key connected to RB3011 (6.47.8)
Suddenly Lte interface disappears as well the modem from the USB device list.
USB power reset works (leds on usb modem shut off and light up again) but no modem back on USB devices list.
Removing hardware and plug it back on USB socket has no effect (light on but no modem listed).
A system->reboot from winbox solves the issue but it reappears in hours or days.
Any hint ?

only support@mikrotik.com or https://mikrotik.com/support
Remember to do and attach supout.rif