I can't confirm that this is a troll, but i got a feeling that he is because he has been choosing the same actresses for LITERALLY EVERY ROLE! Example : he choose Rihanna for Nami in an anime story, this guy doesn't care about the specific ethnicity and age for character roles, he just choose his favourite actresses that didn't fit the character roles. Looking at his casting suggestions, he might be a potential troll.
Username : jeraldhenry (https://www.mycast.io/profiles/39095/username/jeraldhenry)
Again, i can't confirm that this guy is a troll. Maybe it should be looked into. Either this guy is just seeking for attention or whatever reasons, what this guy is doing isn't funny at all. The good/perfect casting suggestions are gonna get bumped by the bad/horrid ones that he chose. I'd recommend you guys to block this user if you guys seeks perfection in your castings and don't want somebody to ruin the castings for the character roles in your story.