I made a function with collapsed nodes in Level Blueprint and it compiles successfully but when i press play it shows there is a compiler error and when i press No the inputs and outputs are swapped and makes a mess. I have recorded a video to better show the effect. Kindly check it out.
Turns out the issue happens because the input node and output node of the collapsed node had the same name (execute). I changed the output name to execute1 for all collapsed nodes and now its working fine.
I request for a feature that warns the user if input/output nodes name are same.
This issue has been fixed since the release of Rocket Beta 3. In current internal builds, the Editor does not even allow you to give the same name to the input and output nodes.
This should not be a problem for you in future releases.