ShaderGraph Expression Node does not throw the Error pop-up for an invalid expression when Node's Preview is collapsed

Steps to reproduce:

1. Create a new URP 3D Template project
2. Create a new Shader Graph
3. In the Graph, add the Expression Node
4. Collapse the Node's Preview
5. Enter an invalid expression - "+++++"
6. Observe that no error pops up
7. Expand the Preview

Actual results: The error pop-up only shows up when the Node's Preview is expanded

Expected results: An error pop-up for an invalid expression shows up regardless of whether Node's Preview is expanded or collapsed. This is the current behaviour for other nodes, for instance, the Swizzle node with an invalid mask

Reproducible with versions: 6000.5.0a8, 6000.5.0b5, 6000.6.0a4

Can’t test with versions: 6000.0.73f1, 6000.3.13f1, 6000.4.4f1, 6000.5.0a7 (Expression node not available)

Tested on (OS): Windows 11, macOS 26.4.1