The most common speculation involved M*A*S*H, with most centering on MacLean Stevenson, who famously left when the character of Henry Blake was extremely popular. Stevenson and the show's producers said that he wanted to break out on his own and be a star by himself, which failed miserably. They tried a couple shows with him, but after that he was relegated mostly to appearances on Match Game. I have read about him being quite the hound on the set. One actress who disappeared after the first season was this one, who played Lt. Dish, and was the actual knockout on the show.
The writer/producer Larry Gelbart also produced the notorious Blame It On Rio years later, a film he made with Stanley Donen, which was shot outside the U.S. so that they could have the 16 year-old Michelle Johnson appear nude and escape child labor laws. The disgraced Bruce McNall, who at one point owned the L.A. Kings and the Toronto Argonauts (and signed Rocket Ismail), was also involved in producing that film. Take that for what it's worth.
Link: https://mash.fandom.com/wiki/Karen_Philipp