Are you using steemitstage.com?

That is the site Steemit uses for testing new (maybe unstable) features. I hear rumours that direct messaging available there already. That could explain the popup message you saw. (i haven't saw it myself yet so can not be sure)

You can check if a post/comment was edited on the blockchain id you wisit the site: phist steemdata.com It contains only the already submitted and registered data from the blockchain sonthere is no way to look into this issue which is most likely was a glitch in the steemit.com (or steemitstage.com) site as you assumed.

You can see your comment and edits under this address:
https://phist.steemdata.com/history?identifier=steemit.com/military/@zombebyte/re-larkenrose-re-ccfoshee-re-larkenrose-dear-brave-u-s-soldier-20171019t165609852z