Several of my orchids, primarily a laeliocattleya and two brassias, seem to consistently create deformed flowers with fused or missing parts. Some of the flowers will be okay but like a quarter will be deformed. And it is fairly consistent, has happened twice in a row in some cases. They don't seem to be suffering from any diseases, look great otherwise. Are there non disease causes? Like low humidity?
Superthrive is added to the fertilizer water... Other than that, I don't know what other mutagen might be involved (some plants are more sensitive than others). Perhaps someone else can jump in...