Mainly it's transformations by failure or randomness, but there are some encounters where you can choose whether or not party members get transformed intentionally, usually in exchange for some supplies.
At least there is some random ones. Failure things tend to annoy me since it feels like your being rewarded for doing things bad. Not sure how your game plays yet, but there are plenty of... naughty games that seem to only give you the naughty on game over, which I kinda hate.
