I just faced an incredible bug in yum module.
When you use state=latest with an enablerepo directive AND yum-utils package is not installed on target server, yum will not update any packages saying everything is up to date.
I spent at least 2 hours looking at the code and trying. All this to finally find a typo in the code. Since i was on a pretty old version of ansible, i checked on devel branch on github and the typo is still there. So surprising this case has not been discovered so far.
Here is the fix : GH8988