Usually when I have seen %eVar name% show up as a literal value in the tracking, it's generally because the name of the Data Element has been changed in Launch, or for some reason the Data Element was disabled/removed from the build (i.e. the reference to the Data Element cannot be found, therefore the literal string is used in its place).
While I know you are pretty sure no changes were made, I would double check that to be safe....
You can also try testing the value of the Data Element... when on the page where it should be populating, open your browser's console and run this:
_satellite.getVar('XXX');
Replace XXX with the name of the Data Element, make sure you leave the quotes.
Example, if the Data Element was called CampaignName; then run:
_satellite.getVar('CampaignName');
If the Data Element exists, it should either return the value you expect or ''
If the Data Element cannot be found, it will return undefined