I used to be able to watch my boy play thru SharePlay and now i get this message: "The Host's game screen cannot be viewed because the game has not been resleasd in your country or region.." Never seen that message before until like a month or two ago. I play on USPS4 and so does my friend.. We've always had this game since ps4 launch so no one re-downloaded it.
It has something to do with the cross console thing i think. Since we now play with pc players that might be why we cannot shareplay anymore on this certain game.
s seems to be a region issue, have you changed your PS4 settings or your friend my any chance, or have any of you moved in the last month?