Recently I suggested edit to tag-wiki on MathOverflow (I am below 20k on that site.) The suggested edit was approved. When I looked at the edit suggestion again, I noticed that I am offered reject button together with this explanatory text (screenshot below):
This suggested edit to your post has already been handled and your action is no longer required.
If you disagree with this edit being approved, you can return your post to its previous state using the Reject button below.
This does not seem to be specific to one site, I found the same behavior on sports.SE (screenshot below).
If I understand this correctly, the system consider me as the owner of the post, since I created the tag-wiki. And then, since a suggested edit was made to my post, the system offers me a possibility to reject it. (IIRC the post owner has the final say on suggested edit and they can vote to approve or reject suggested edit of their own post, regardless of their reputation.)
However, it seems to me a bit illogical that I have a possibility to reject my own suggested edit. I think it would be better to remove this option. (I.e., you should not be able to vote on a suggested edit on your post if it is your own suggested edit.)
Screenshot from MathOverflow:
Screenshot from Sports: