This. This right here. It drives me absolutely insane.
To reiterate the issue: When you type a hyphen into the tag field, autocomplete fires, accepting the top suggestion, injecting it into the tag field, and moving your cursor to the end of the line so you can begin typing the next tag. Well I wasn't done typing this tag! Why does typing a hyphen mean I'm done typing out a tag? Why would you assume the first alphabetical autocomplete option is the right one? It's a madhouse! A MADHOOOUSE!
In short: I expect to be able to type hyphens freely into the tag field without anything clever happening. Typing a hyphen shouldn't do anything automatically. I would expect autocomplete to fire when I type RETURN or COMMA or perhaps TAB. All of these seem pretty typical. Firing autocomplete when the user types a character commonly found in a tag name seems absolutely crazy to me.
Here's a video of me being driven to distraction by Evernote's overzealous tag completion: https://cl.ly/3N3h1k2K3N3d
(Also: This happens on all Mac clients but just so I don't get asked, I happen to be using v6.8 Beta 2.)
(Also also: This does not happen on iOS, where things behave as I would expect. Namely, the result of typing a hyphen is that autocomplete suggestions update, just as if I'd typed any other standard character.)