After editing a script to add one or more attributes of type entity, I go back to the editor, select the object with the script assigned and refresh the script, so the new attributes appear.
Then I drag and drop in the new attributes some entities from the hierarchy, and it shows them assigned. But is not true.
If I hit play, or I just unselect - select the entity, the two attributes are empty.
The only way to fix this is to refresh the editor and reassign the attributes again.
It already happened multiple times, so should be reproducible somehow.