Unfortunately, just as with multiple-choice questions, answers will have to be submitted manually on iPhone app, because unlike desktop and Android it does not have API for this functionality.
I’m not sure about this behavior though, was your experience different from what’s shown in this post?
This should already be fixed in the current version of the branch. You can access the latest state here (the link in my previous post leads to a fixed state, which is obsolete now):
the source code for cards is stored in the “Add-on/Source code” folder.
It should have all the known bugs fixed at this point. Although I still keep coming up with ways of introducing new ones and could use a hand with testing.