All appearance icons saving as red?

When I edit an appearance & save as a new one to the library, the icon is always red in SolidWorks 2018. The appearance applies correctly but the icon is wrong. These are custom materials created in an earlier version of SolidWorks. If I edit an existing SolidWorks 2018 appearance & save as a custom appearance then the icon appears correct.

Is anyone else seeing this, know of a fix or a work around?

SolidworksUser Interface