This looks similar to the issue mentioned here and is due to a known issue with Unity. Deleting the Library folder and reopening the project should resolve the issue.
Please let me know if you are still getting these warnings and I will investigate further.
EDIT: Looking at our issue tracker, I saw there is also a known bug which causes these warnings after new events are created and banks reload. This should be fixed in the next release, which should be available soon. When that becomes available I recommend updating and seeing if that resolves your issue.