Hello again Dama,
Hope you are doing well and votes of success for 2019!
After a little more research, I found that the retaining cycle is related to the completion within each Wireframe. Sorry for taking so long to answer but I was only able to look at this again today.
var completion: ((String) -> Void)?
var completion: ((Currency) -> Void)?
var completion: ((()) -> Void)?
If the flow has multiple steps, like the ExampleFlow present in the sample project, neither the UIViewControllers or the Wireframes will be released.
I really look forward to fix this in order to adopt this approach and, if possible, to improve it for our needs!