Bug Performing Drag on VisualElement

Hello! I'm trying to build out an EditorWindow that allows you to drag a label (without actually moving it) to object field slots. When you start dragging the label, and GameObject type is populated.

I was trying to follow along with instructions on this doc page

The problem:
Everything works well, but I can't seem to figure out how to end the drag when dropping into another window. I end up getting console errors, even after I've stopped dragging:

Code (CSharp):

1. Drags can only be started from MouseDown or MouseDrag events

Here's my current setup, hoping someone can give me direction so I can wrap this feature up:

Code (CSharp):

1.  
2.         dragLabel.RegisterCallback<MouseDownEvent>(OnMouseDown);
3.         dragLabel.RegisterCallback<MouseUpEvent>(OnMouseUp);
4.         dragLabel.RegisterCallback<MouseMoveEvent>(OnMouseMove);
5.  
6. ...
7. ...
8. ...
9.  
10.     private void OnMouseDown(MouseDownEvent evt)
11.     {
12.         dragReady = true;
13.         DragAndDrop.PrepareStartDrag();
14.         DragAndDrop.SetGenericData(interaction.name, interactionObject);
15.         DragAndDrop.objectReferences = new UnityEngine.Object[] { interactionObject };
16.         DragAndDrop.visualMode = DragAndDropVisualMode.Copy;
17.     }
18.    
19.     private void OnMouseUp(MouseUpEvent evt)
20.     {
21.         dragReady = false;
22.     }
23.    
24.     private void OnMouseMove(MouseMoveEvent evt)
25.     {
26.         if (dragReady)
27.         {
28.             DragAndDrop.StartDrag(interaction.name);
29.         }
30.     }

Something keeps setting the value of dragReady back to true, even if I'm not clicking an element. Any guidance would be greatly appreciated, thank you!