Apparently this issue is affecting both the Galaxy S6 and Galaxy S7 owners and it only seems to be glitching out in Samsung’s stock email app, so it’s not as if it is affecting the entire device. According to the poster in the forum, “Stock email app on GS7 Edge having typing issues. Whenever I try to type contractions like I’m it replaces the ‘ with ” and deletes any letters after auotmatically. It also changes words like autocorrect into aautocorret and three to ttree… Autoreplace, autocaps, autospace and autopunctuate are all turned off.”
As speculated by SamMobile, it is possible that there could be some kind of server-side update that Samsung might have pushed out to the keyboard or the email client that could be causing the issue. As it stands it doesn’t seem like too many users are affected so maybe the problem is contained for now. There does not appear to be a fix or workaround, so hopefully Samsung catches wind of this and fixes it ASAP.