inconsistent across certain browsers

This plugin has been awesome for me for quite some time, but in the past couple of days its been acting up.

I activated it and the MU plugin for a routine conflict test, just like all the other times I’ve done it. Normally I could go to another browser (private or otherwise) and check to see what the frontend issue would look like and wouldn’t have any issue.
But, this time around the browsers were all showing slightly different versions of what I was editing, and some of them simply would not update along with the edits. I thought it was a cache issue, and even reinstalled my main browser.

But, the issue was with this plugin. Any one have any experience with this sort of thing?