Shapes doesn't work with WebGL 2.0 if hardware acceleration is disabled

In a WebGL game shapes was not working when the browsers hardware acceleration was disabled, the console was flooded with 

"GLSL link error: Vertex shader active uniforms exceed GL_MAX_VERTEX_UNIFORM_VECTORS (256)"

and nothing from Shapes rendered.

This was fixed by disabling "Auto Graphics API" in Project Settings > Player > WebGL > Other Settings and removing WebGL 2.0 from the list of graphics APIs, so that the game would default to using WebGL 1.0.