This is a new bug in the 4.11 Preview, it did not exist in 4.10. If you place this node in a blueprint:
Even if it’s not connected to anything, just floating around, you can’t call any functions on that blueprint any more.
Here you have a repro project: Google Drive: Sign-in
If you hit “1” then you should see a print from a blueprint. You don’t see it. If you go into that blueprint (Cube Blueprint) and remove that node I talked about, it will work.
This bug only occurs in standalone and packaged, not in PIE, so make sure to not test it in PIE