De-select an item on node/*/edit does not work on single value field

I created a node and added selected item and saved the new node.
When I edit the created node, I de-select the item in the entityreference field (de-selecting checkbox on the node edit page, not in the modal) and save the node, then the node is saved with the item. The field value is not empty.

I mark this as major bug, because deleting a field value is main part, that should work.