I just approved a suggested edit on this post. Presumably, the edit was started before Oded added status-declined, and so the suggested edit was submitted without that tag. This is a regression of a formerly-fixed bug.
The fix implemented in the past only of the case where a user won the re-tagging race against a mod. For that to happen we the mod had to open the edit UI before the (suggested) edit was save. However, it did not take care of the case where the order of events was reversed.
Now, whenever there a normal user tries to save a (suggest or full) edit, and there is a new revision which has mod-only tags (whereas the revision the user is editing hasn't), the user will get an error message prompting him to apply his edits to the latest revision. Unfortunately this requires reloading of the page. Luckily though, this is merely enforcing users to act as suggested in the realtime notification on top they already see.
The described fix will roll out with build rev
2014.4.23.2183 on meta and
2014.4.23.1563 on sites.