LTE 4G Modem on WAN appears to sleep/disconnect

[berriferous]

I'm running PFSense on a Protectli 4 port vault. I have a Tmobile 4G LTE MF915 cellular modem/router connected via a USB connection. PFSense recognizes the modem as a USB network card: ue0, and I have it configured as a WAN. My wired WAN is currently disconnected, leaving the wireless router as the only connection to the internet. When initialized and used, it works great. If I power down the computers connected to PFSense, say overnite, the internet connection seems to disabled when I attempt to connect to internet in the morning upon powering up the computers. I have a secondary wireless connection into the cellular modem (in other words not through PFSense wired USB, but the modems wireless AP.) It also tells me I have no connection to the internet. If I reboot the cellular modem OR I disable-then-renable the ue0 adapter via the PFSense web interface, the internet connection comes back online. Is it possible the USB ethernet/modem connection is sleeping? And is there a way to disable it?