Ps + multiple accounts?

Today I tried to put a friend's account on my Ps4 primarily, even though he had already shared his account with someone else, somehow that didn't work, because it meant I should first deactivate somewhere else, so possibly on the pS4, mine Friend also shared the account.

Once I shared my account with 2 friends and they could both play my games. Why is that?

I have primarily activated on another account on my Ps4, do I have to activate it there maybe?

You can't share 2 people at the same time. So if fu primarily wants to activate from your friend's account, he must first deactivate.

Then how was it with me?

I don't know that 2 people suddenly sharing is not possible. The person who did not get Primary PS4 from your account then either got the same game shared by someone else or the license or it would be a lock before the game.

I think it was kind of a bug: /

So I need ps Plus, so far I could always do it myself for free, now the method is no longer possible, and with this method with a fake credit card I'm never sure… Somehow a strange feeling, do you think something can happen?