I have noticed that when importing PA/Flows from a solution, if using the CDS connector (not CDS Current Environment) or a number of other connectors, the connections break and each individual node needs to be specified as what connection it should use. Sometimes this is problematic as Flows can be quite large and each individual node can be buried in condition and loop logic.
I believe there should be the ability to fix these connections centrally. The reason I say this is that the "Save As" functionality already does something similar. However, this is not a viable fix for the issue because it leaves the broken Flow there, and the new one is no longer inside the solution.