Sounds like the click spring is broken. Not something you can fix yourself unless you know what you are doing, but an easy fix for a watchmaker. Next time you need the battery changed, take it to a watchmaker with an Omega parts account and they can take care of it.
Donn is right, they are difficult to find. I have had a few watches that this has has had this fault, people don’t normally turn the bezel and they seize and a lot of people don’t know they only turn anti clockwise, so people force them and damage the tabs, if they are stuck I normally give them a little squirt with WD40 silicone spay.
I have attached a picture of what they look like, they are fairly easy to change if you have the tool too remove the bezel.
