Weird problem with max number of ip

Me and my friend are sharing bot 1 pc for me and 1 laptop for him
But whenever we give 3rd ip to any1
We always get max number of ips used every few days
We’re 100% sure that every1 using 1 pc or laptop only what’s the cause of this problem?
Ofc i tried everything like reset pw to make sure only 3 of us got the pw
Also got suspicious and changed the 3rd ip owner and still same problem happens

It’s hardware not IP address. The hardware is changing on one of the PCs or Windows is randomly returning different data for the HWID. There is nothing I can do.

yes I know it’s hardware , but isn’t it something like pc’s mac address? which should be unique and fixed ? how can that change ? no1 change anything in his pc , no new windows no anything ?! how is that possible ? please help me

Enabling/disabling network devices may change it. That includes VPNs.

do you mean if i restart my router for example it will change my hardware ?! that’s weird man … this should change the public ip only … idk how is that related to hardware
and about VPNs none of us use it .

No. I am talking about network devices inside Windows.

no man me and my friend are online 24/7 , neither me nor him does that otherwise all chars will dc and relog again with new network , but i’ll check that again for him.

as you see I have only one ethernet network in my pc , i’ll check my friend’s laptop.