There was only one major cloud that threatened to sour his career as a Ranger, and that was the circumstances of his departure from the show. David Yost quit only two episodes from the end of the Power Rangers Zeo series, and producers had to reuse stock footage and a body double in order to make it look like he was still there.
It's still unclear what happened to make him leave the show so suddenly. According to producers on the show, Yost left because of a contract dispute, after a promised bonus salary was not delivered to the actors. However, Yost has a different memory of it. In 2010, David - who is gay in real life - told an interviewer that he quit because the working atmosphere had become toxic, and that he was constantly subjected to homophobic slurs from the crew (but not his fellow cast members) whenever he was on set.