I have been editing logic in the data variables.
I noticed following behavior. I add new "Receive event" select any of the available events in the "Event source". Click Save button.
The name of the function on the screen remains "Event / Receive event". When I click on the function, I see that Event I have selected was not saved. I select the Event again. This time the name of the function changes on the screen "Event / Name of the selected event" and when I save, it stays saved.
In summary it works in the end, but you need to select and save the event 2 times.
Probably some minor bug somewhere..