well instagram bans all accounts on an ip, even if there not og, just if there is a shitton of accounts on it.
they think it is an open proxy , and the ip gets flagged after like 10 accounts signed in/created within an hour period or so on an ip.
I am not sure if its the exact same, but ik for a fact when delivering followers, that you cant login to 10 accounts on an ip within an hour unless you wanna say bye bye to the accounts.
and to add on, they instantly ban them all at once, so it is system automated.