PS4 Trophies / User Accounts?

I have a question regarding the PS4 trophies. Do not know me with Playstation have currently borrowed the console from a friend, but already noticed that I play in digitally downloaded games that I play on my account that I have it that he bought them with him no trophies (Have tried it several times).

Now my question is what if I insert a game with a disc and he has played this game sometimes, then I can also get no trophies so I have to log out of his account necessarily from the console?

So that you do not get any trophies with your games on your account, I think quite strange, that should actually go. I even occasionally use a second account on my PS4 and still get it with trophies.

Have read somewhere else if he has already received the trophies, I can't get these too: / But funny that it seems to work with you =

If you copy foreign scores to your account, you can't get any trophies. Otherwise I can think of no other reason!

Got your own score created strange. Yes, then I just try it out if it works with disc. Just annoying if I'm extra careful not to miss a trophy and then not get it

Try trophies that are easily accessible.