GLSL: unsupported array parameter 'unity_LightPosition' (and 'unity_LightColor')

On our crash statistic page I see some GLSL errors coming in that I can not explain. They are

GLSL: unsupported array parameter 'unity_LightPosition'

and

GLSL: unsupported array parameter 'unity_LightColor'

I’m not using unity_LightPosition in any of my shaders, and I’m using unity_LightColor in one, but it seems to work fine. The users that report these issues are using fairly old android devices (e.g. samsung SM-T110, samsung SM-T2105, SM-G313HU, etc.).

Is this just Unity complaining about an unsuported GL feature, or is it something else going on?

Note: using Unity 5.6.3p4.

I changed my Graphics API for PC in Player Settings → added OpenGL core and Unity editor does not display properly (All editor windows are white).
Error message is
“GLSL: unsupported array parameter ‘unity_LightColor’”

This probably means hardware support problem.