Also reproduces on this backport for 9.x.x, and was probably introduced in the PR it is backporting
https://github.com/Unity-Technologies/Graphics/pull/1488
Repro steps:
1. Use a project with HDRP
2. Create a HD Lit shadergraph
3. Add a virtual texture property to the blackboard and drag it onto the graph
4. Hook it up to a Sample Virtual Texture node
5. Click the node and, in the internal inspector, change the Lod Mode
Expected result: the output slots remain there
Actual result: the output slots are deleted