Some Material Nodes Are Not Able To Be Deleted

There are a lot of cases where nodes in the material editor will no longer get deleted even if you save the material after deleting the node. As soon as you close the window for the material editor the nodes come back and the thumbnail updates to reflect this.

The repro steps are the most basic example of this however you can run into this issue with many other nodes and it appears that just deleting nodes within the same tree causes issues.

REGRESSION?
Yes

Did NOT occur in 4.15.2 CL 3416026

Found in Binary Preview Build 3___ 4.16 CL 3427662

1. Open a Blank project
2. Create a new material
3. In the graph create a scalar parameter and a multiply node
4. Plug the scalar into the multiply and then the multiply into base color (see screenshot)
5. Compile and save
6. Delete the scalar then save and close the material
7. Open the material

RESULT
The scalar node comes back and isn't deleted.

EXPECTED
The scalar param node is deleted.