This edit conflicted with a subsequent edit.
See the FAQ for an explanation:
If a user with full editing privileges for a post (including the original poster) begins editing the post at the same time as you, and they save their edit after you have already suggested it, then your suggested edit will be overridden in favor of their fully-privileged edit.
Possibility 2 (not in your case, but for the sake of completeness)
Another way this can occur is if a fully-privileged user makes an edit, then you suggest another edit right afterwards, and then the first user makes another edit during their 5-minute grace period. In that case, a new revision is not created, but your suggestion is still automatically rejected due to the edit conflict.
However, the good news is that this won't count towards an automated edit ban.
Now, I will add more to answer your actual question:
Why would an edit get auto-rejected because of another irrelevant edit?
The editing hierarchy goes somewhat like this:
- OP and moderators
- Users with edit privilege
- Users without edit privilege (includes unregistered users)
It does make sense to place the OP above other users,
- so they can prevent other users from completely changing their
question -> If they abuse their right, a moderator can still step in
- and directly edit in necessary information -> If they could merely suggest an edit, it could well take quite long for the edit to be accepted (especially on smaller sites) or even be rejected by a robo-reviewer.
Now, regarding the irrlevant edit - it's an automated process and how do you measure relevancy? Even a small edit may make a great difference, e. g. a decimal separator or location info ("US", "UK" etc.), to answerers.
There are several ways to deal with the concurrent editing problem, but SE finally chose "optimistic concurrency". That's the feature request that made them implement it.
I guess the chances that something changes are pretty slim. First of all, this is considered an "edge case" and in general, rejected edits are not considered a great problem (just 2 rep, you need many to get banned). I know how you feel, having experienced this myelf, so I do not fully agree with their reasoning. But in the end, they would probably argue that they needed a better system and that it wouldn't be worth implementing it. See for example how people tried to mitigate the problem by improving the stats here and here and how much has changed since then...
Changing such a core functionality of SE is out of TWP's scope, so you'd have to post a feature-request on Meta Stack Exchange (possibly already exists, but I didn't find one). I guess you needed to make clear why it's a problem that needs to be solved and how to solve it. Perhaps you could start with a discussion first, but I guess they would deem it not to be an actual problem. That's what I learned from reading about edits.
What can you do?
- Respect the grace period. It depends on the OP, some edit their question furiously, others post it and then never come back. But if you wait for 5 minutes, the risk is not that great.
- Be fast. Read the full question so you know what to improve. This way, you are much faster than keeping open the edit window for too long.
- Keep track of changes. You are notified at the top if the post was edited in the meantime.
- Get the privilege - 2,000 reputation on TWP. Considering how fast you are gaining rep, you will soon get it.