Changing Mode of Light from "Realtime", causes shader errors on iPhone.

I see "...vertex mismatches...", if I change the lighting from Realtime to Mixed. I see no detailed errors that I can share. It just prints the following and I don't see the light and the surface it hits.

What can be the problem? Must I use realtime lighting on iOS?

 Metal: Error creating pipeline state (Standard): Fragment input(s) `user(TEXCOORD8),user(TEXCOORD5)` mismatching vertex shader output type(s) or not written by vertex shader
 Metal: Error creating pipeline state (Standard): Fragment input(s) `user(TEXCOORD8),user(TEXCOORD5)` mismatching vertex shader output type(s) or not written by vertex shader