Reproduces in Master going back to 10.2.2
Doesn't repro in 9.0.0-preview.73

Repro steps:
1. Create a Universal Lit shadergraph
2. Plug an add node into the master stack's base color input
3. create a float/vector1 node
4. Plug that node into one of the add node's inputs
5. The base color should be black due to both inputs to the add node resolving as 0
6. Change the inline input to the add node that is not plugged into to the vector1 node to 1
7. Undo
Expected result: the node previews and main preview turn black
Actual result: the node previews and main preview don't update; even fiddling with the graph won't make them update, the only way to make them update is to manually enter something into the inline node input, or save the graph and reload it.