Currently, mass editing badges while removing them from previous holders results in people getting a badge removed and immediately regranted, if they are in the intersection of previous and future holders.
This results in a confusing user experience, as users receive a notification about receiving the badge even though nothing has changed.
Also, it clashes with one of our use cases: We would like to drop obsolete badges and award new ones by passing the updated list of holders, while keeping the other holders and the date of awarding unchanged.
Feature-wise, change would be is a strict improvement: By uploading an empty list first, the old behavior is recovered.