I am using LTE internet via Huawei 3372 and it stops for about a minute or two exactly 6 hours after starting the modem (of course during some important call).

I am using LTE internet via Huawei 3372 and it stops for about a minute or two exactly 6 hours after starting the modem (of course during some important call). After it, existing connections continue to work. I'm curious to know what might be causing this.