There are user revisions re-edited by other users to get back to the same code.
If there are, please flag and report them. There is still a 6 character minimum to suggested edits, and minor edits should be rejected in accordance with guidelines. There's nothing wrong with multiple users editing a single post, or even a single user editing a single post multiple times, as long as the edits are substantial and positive.
As far as I know, that can be used to gain reputation (until you get to +1000), and that's annoying to the user posting the question.
As stated above, we trust the people who are approving the edits to make sure that frivolous edits are rejected. After you get up to 2k rep, you don't gain reps from editing any more, nor would your edits need to be approved.
Is there any way to stop this? Maybe limiting edit rights for some time?
If a certain amount of your edits are rejected in a short period of time, you'll be barred from suggesting any more edits for a week.
And, if someone makes a wrong edition, I suggest there should be ways to roll-back your own edition or modifying it when your not the user posting the question. Ie. I cannot roll-back my own editions in other users' posts like this one
The rollback option is available to users with editing privileges and the original poster. I don't understand why you might want to enable the editor to do rollbacks, since it would make the current system more complicated, while should not see much use in practice and would only make it easier to start edit wars. If you have a genuine complaint about an edit, post a comment or flag the post.
In addition to all these, it might be a good idea to read up about how the suggested edit system works - there are two different set of rules that apply to those below and above 2k reputation. It might be a good idea to get acquainted with these before coming here and complaining about non-issues like you did originally.