Just for clarity's sake, swiftkey's swipe to type option is called "flow".
Sorry I don't have an answer. I would send a support question into swiftkey, which has been responsive to me in the past, and see if they have an answer.
For Thom's sake, the issue is that swiftkey has a feature called flow that allows you to trace through letters on the keyboard without lifting your finger to input words, rather than tapping on each key. Google's stock keyboard supports this as well, which they call "gesture typing". And rogerl50 wants to be able to use a feature that tetra supports to reply to messages without unlocking his phone.
Again - I'd try contacting swiftkey and see if they can provide an answer, or perhaps an update that fixes the bug you're having.