Tyler has (/had?) a student visa and Zhang Yuan is (/was? I don't know if anything has changed by now.) under a foreign language teacher visa. Neither of these is good for entertainment work. Tyler got fined. But somehow, they were allowed to continue the show, if they just limited the endorsing activities.
Aussie Daniel left the show. He was said to go back to Australia to study but then posted to instagram that "ㅋㅋㅋㅋㅋ What studying. ㅗ Me, study?" and later deleted that and claimed his account was "hacked". People speculate that he, too, had visa problems just like Tyler and Zhang Yuan, but that while JTBC sorted out Tyler and Zhang Yuan, they didn't do the same to him.
Now,
Enes' scandal is all his own doing. A woman came forward with
screenshots of her and Enes' conversation that strongly hint that he has
been... acting like a single guy (he is married and his kid was born
just last year). Having affairs. She had some voice recordings and photos in effort to prove it was Enes. Then another woman came forwards saying the same.
Enes
initially stayed quiet, withdrew from the show, and has now lawyered up
and released a statement (defamation, misunderstandings, "will reveal
the truth through law".... So the usual.).
Ah, it's such a mess.