Why is my gateway broadcasting 6 of 2.4GHz networks, which I have not ever set up?

Hi, I have Arcadian gateway which I got a month ago, and have setup one network with my username and password different from the one provided on the device. I have noticed on multiple occasions that my iPad shows 6 networks broadcasting, from my gateway. These networks have the same SSID as the default one, provided with the gateway with some extra (-2.4GHz_1).  Es así:

TMOBILE-7xxA-2.4GHz_1
TMOBILE-7xxA-2.4GHz_2

TMOBILE-7xxA-2.4GHz_3

TMOBILE-7xxA-2.4GHz_4

TMOBILE-7xxA-2.4GHz_5

TMOBILE-7xxA-2.4GHz_6

They are all password protected as I see a lock icon but I haven't tried to connect to any of these. After a minute of showing up they disappear. This does not happen everyday, only occasionally. In the T-Mobile app, I only see the network which I have setup with custom name and password. Is my gateway hacked? Why is this happening and what should I do to get rid of this issue? Gracias