SSID names not matching - Putting a 2 after name

Hello,

as written in the title, I have an annoying issue in both a Vista and a Win 10 based pcs.

I have a Netgear router working with the network named "XXXX"

On both the computers I have the network visible and working, but with the name "XXXX 2".
No way to change it to match the SSID name in the router settings.

On the available wifi connections in Windows I see the correct SSID name, but when I connect the pc to the router I get the "XXXX 2" name in the properties of the network and passing the mouse on the wifi icon in the right below corner of the screen.

I have erased all the known networks from the windows lists and made a new connection, but nothing changes I can't get the correct SSID name.

I have also tried to change the name in the router, but if I return then to my original name i get the number 2 added to it.

Wht's going on?

Network is working, but I'd like to understand what is the issue.

Thanks