I don't think so, the "movement" of the pistons feel smooth when I push them back in.

My current hypothesis is that there is some issue with the flow of oil back and forth between the lever and caliper. After pushing the lever, causing the pistons to come out, the seals (probably) of the pistons push the pistons back just the tiniest bit, but not as much as the've come out from the lever action.

Cheers