Interesting, I've not seen that happening at all whenever I have tried with a JioFi. So I use a outdoor LTE device with a Jio sim and I have been able to get only a single IPv6 public address. I have not investigated much though as I always thought it is not possible. Will do some testing in that case.
My outdoor LTE device is in bridge mode and my main OpenWRT router is what gets the main IP address etc.
This sounds like those Lte cpe unit, can you post a link to the unit ? does it have a directional antenna ?, i have line of sight to one of the tower so i would like to get a directional antenna based lte cpe if they exist to get the most reduction in noise, i was going to an usb lte modem on openwrt connected to a directional antenna on the roof for a second failover wan with openwrt
also if it was from AliExpress do you mind sharing how much you paid in taxes