I have been a forum moderator in the gaming world for over 20 years, so I have a little experience here.
My suggestion is that when moderators make changes to a post, they are required to add information at the bottom of the post about why the edit is made, and by whom.
This has served us well in forums where a flame-war may break out any moment.
However, our habit is to ask the OP to make the edit themself so that they learn.
Only rarely will we ever edit someone else's post if they are still an active member.
Editing other peoples posts is seen as very bad form. Not just rude but an invasion of speech, so should be a last resort, not the common practice.