I have rank VIP, and it is a parent of defeault rank, is possible unparent buy only the rank prefix?

You've not really given me much info to work with.

Which placeholders are you using?
Which commands are you using to set the prefix?
Screenshots of the info and meta info commands for the users with incorrect prefixes?
Screenshots of what AnimatedNames is actually showing?

Please re-open this issue after providing the above details.