Whilst I still think the new flow is clearly a step backwards, I have found yet more bugs in it.
This is SwiftKey 18.104.22.168 on a Samsung S7 running Android 7.0.
1. If you just straight up flow a url, you get this:
http://google .com (extra space inserted before the period)
2. Now I want to go back and prepend "drive" to "http://google.com." I put the cursor in the correct position and flow "drive." Now you get one of two options, seemingly arbitrarily:
http://drive .google.com (extra space before the period)
http:// drive. google.com (extra space before "drive" and after period)
I have no idea why one happens or the other.
At no point do you ever go near the spacebar, but there's spaces everywhere.