Repro steps:
1. Create a new URP Lit graph
2. right click the vertex stack in between stack nodes and choose "create node"
3. Choose "Custom interpolator"
4. Right click the graph and choose Custom Interpolator -> CustomInterpolator
5. Plug it into Base Color
6. Create a Texture2D property
7. Create a Sample Texture2DLOD node and plug the property in
8. Create a Sample Texture2D node and plug the same property node into that as well
9. Plug the SampleTexture2DLOD node's "RGBA" into the CustomInterpolator vertex stack block
10. Plug the SampleTexure2D node's "R" into the "Smoothness" fragment stack block
Expected result: the graph compiles, or does not let you connect the Texture2D property route into both vertex and fragment stages
Actual result: the graph gets a compile error