I used to work at a major manufacturers distribution centre and transit damage was quite common.
The standard for new cars (especially for private customers) was different from used vehicles even if the used car was only pre registered and had a few miles on the clock.
Basically any dent that could not be repaired using high build primer was classed as used and couldn’t be sold as new, it was a no no to use filler on a new vehicle so it wouldn’t surprise if a complete new door is fitted rather than using filler to repair the door or re-skinning it.