When any Node is converted and replaced to Sub Graph then reloading the same "New Shader Sub Graph" causes the Editor to throw multiple exceptions, Refer attached video.

Steps to repro:
1. Create a new HDRP template project
2. Project window > Create > Sahder > Sub Graph > Open
3. Create a Node(eg. Flip)
4. Select Flip Node > to right-click > Convert it to Sub-Graph > Save and Replaced
5. Graph has changed on the disk > Reload
6. Select Flip Node and move

Actual Result:
Multiple errors are thrown when Node is converted to Sub Graph and Realoeded the Sub Graph

Expected Result:
No errors in the console.

Reproducible in:
2020.2.0a20, 2020.1.2f1, 2020.1.0a23 with Package version 10.0.0-preview.27, 9.0.0-preview.33, 8.2.0, 8.1.0, 8.0.1

Working Fine:
2020.1.0a23, 2019.4.7f1 with Package version 7.4.1

Environment:
Occurring on Windows 10 & Mac 10.15.