Changing matreial names in Blender breaks the link to node trees.

[TzuChieh]

This problem can also appear when appending materials/nodetrees from other blend files.

[TzuChieh]

This should be fixed in Blender 2.80 as now node trees can be pointed at by bpy.props.PointerProperty. No longer using names to lookup.

Pending for confirmation that this is actually fixed...

[TzuChieh]

• [ ] Check if this is fixed after 3.6 LTS