I've been testing/trying out the follow post feature.
In this post, I was not notified of the edit. The edit was suggested and approved (not a direct edit). To be sure I checked my global inbox, and it's not there.
For the timeline of events: I've been following (and still am for troubleshooting purposes) since Sep 17. Edit was Sep 18, and was suggested not before, but after my following, as it includes my improvement suggestion (OP is unregistered, and they created another account to make the edit).