Fragment shader failed to compile. too many uniforms

Tested on iOS 12.2 devices I seem to get this error consistently after adding multiple imagery providers with defined rectangles, then when zooming in beyond level 11. with 2 or more imagery provider rectangles within the visible range and terrain provider added to the viewer I receive this error:
"RuntimeError: Fragment shader failed to compile. Compile log: ERROR: too many uniforms"

I can never reproduce the error when I only have one imagery provider added to the viewer.

No source file, test, or entry point is named. First reproduce on an iOS 12.2 device with multiple imagery providers using defined rectangles, terrain enabled, and zooming beyond level 11. Done means the fragment shader no longer fails with “ERROR: too many uniforms” when two or more visible imagery-provider rectangles are present.

Written by the indexing model from the issue text.