A lot of this goes back to changes to offside over recent years and now "phases" where a phase can be less than a second in time.
As a certain Mr B Clough of Nottingham used to say "If he isn't interfering with play, what's he doing on the pitch?"
When the free kick is played there are 2 Villa players standing in the middle of the 18 yard box but not deemed to be "interfering with play" and can receive a 5-10 yards headstart on any defenders coming back into the box. However if a defending player is lying injured on the floor or even off the pitch behind the goal-line during play then they are always deemed to be active.
Also why was Konsa allowed to return to his defensive position on the pitch before the goal kick was taken (after having received treatment for his bloody nose) whereas Dalot had to go off the pitch before a corner was taken (after receiving treatment for his bloody foot)?