This drives me bananas too. Is there a way to "fix" this? For me: 90% stock keyboard; 10% SwiftKey, although SK's predictability is second to none.
I was busy earlier. I'm out of town with my son, who had back surgery yesterday. He's 27. Anyway, here's what probably needs to be done to fix this email issue.
1. Do like I did and either delete or change shortcuts that won't lead to anything other than the email. For example. If you use
sanibel@icloud.com, and you use sa as your shortcut, then every word that begins with sa will pop up the email address. So I now use shortcuts that nothing else would use. Like @@, or ??. Anything another word would not use. But that's not enough. I think all the old shortcuts are still in the dictionary memory. So..
2. Reset the dictionary. Go to Settings >General >Reset >Reset Keyboard Dictionary.
Hopefully that would work. I have yet to test that by resetting the dictionary.
Sent from my ancient but trustworthy iPhone 5.