I heard that they got too slow on short final, resulting in the FBW system trying to stop them from stalling / preventing them from flaring.
Haven`t flown the P500 yet, but the P600s autothrottle can be a bit slow and thus it is possible to get a tad slow. The P500s system is the same, wether the derated engines make em more sluggish in response I donīt know... can somebody with experience on both comment ?