Hi John. I’m looking at your render, but I’m not sure I’m seeing the “oddness”. Perhaps it’s my eyes, but could you explain what is going on for you?
Edited to add: Oh, wait. Don’t answer. I see what you mean. I had to go in and look at the close-up of the legs. D’oh. Silly me.
I might actually know the answer to this. :D First, did you use a pose preset to create this? If so, the problem is that the pose preset has information in it that pertains to the foot bones. These have to be removed first, or completely zeroed out in order for the foot fins to behave. It’s a quirk of the geografting.
I should point out in a shameless plug that all of the poses in The Deep Ones have been optimized for the geografted fins to avoid any “fin jump”. :D