Switching Build Target Breaks some materials, requires Reimport All

When I want to switch to a new build target or architecture in the "Build Settings..." menu, Unity seems to mishandle assets. Most of my materials become "problem pink". I have to do a "Reimport All" to repair the broken materials. If I switch back to the original Build Target & Architecture, the materials do not reappear. It seems like the material component just gets lost on the GameObjects.

Submitting a bug report.

 

Case #817898