Issue Resolution Details for current release (v29.00):
Backwards compatibility enforcement in UEFN has been disabled. This fix will require you to restart UEFN.
A fix has been pushed to Creator Portal. Backwards compatibility checks will still be run as part of the Creator Portal publishing workflow. Backwards compatibility issues detected during this workflow will prevent you from publicly releasing incompatible changes.
This issue will be fully resolved in the next release. The fix is already in place that fixes the underlying backwards compatibility validation issue in UEFN. Once the next release is live, backwards compatibility enforcement in UEFN will resume.