Migration from 4.12.5 to 4.13 can result in Blueprint functions losing input/ouput variables

When migrating project from 4.12.5 to 4.13, Blueprint functions can lose input/output variable links.

1. Download attached project
2. Open 4.13 and browse for project, open downloaded project
3. Save as copy, as 4.13 version
4. When editor is open search, "Island" in Content Browser
5. Open "BP_Island"
6. In functions tab, on left side of window, drag ApplyRotationInternal function into Event Graph
7. Double click ApplyRotationInternal function

RESULT:

Direction input visible on function isn't on Input node.

EXPECTED:

Migration keeps input/output nodes on Blueprint functions