Crash when trying to set path referenced material

Steps to reproduce:

1. Assign copper as a material to some mesh
2. To any other mesh make the absolute referenced material to the copper from step 1
3. Change copper to some other material
4. Restart editor and confirm that mesh from step 2 is not rendered
5. Change some other material back to copper
6. To the mesh from step 2 make the path referenced material to the material from step 1
7. Editor crash

Expected to be able to make path referenced material without crashes