Steps to reproduce:

1. Create a custom shader for UI with the default implementation (branch node with default inputs)
2. Load RenderDoc from the scene vew tab context menu
3. Notice that the preview has disappeared in Shader Graph and it won't reappear even when resizing the preview subwindow.

Actual results: 

Preview disappears. Window layout must be reset or editor restarted.

Expected results: 

Preview remains

Notes:

• When using an unlit/urp shader, the preview also disappears for a moment but by resizing the window it forces a refresh and the preview reappears. It doesn't do that with the UITK preview