Currently, undo/redo takes you to the location of where an edit occured, but you cannot see the edit undone or redone. You have to hit undo/redo one more time for the edit there to actually be replayed (or undone) - the problem is that when you hit undo/redo the second time it takes you to the next place where an edit/undo could occur. This is different than any other undo/redo following logic that I've seen, and it's not how it happens in Vim. I believe this may be the default sublime undo/redo logic - not sure.
Are issues for Vintage still being tracked or worked on in github?
Note: You can see the behavior clearly when making changes at different ends of a large file.
This is not a Vintage issue - it's a Sublime issue.