QSG_VISUALIZE=overdraw causes precision mismatch error when using ANGLE on WP8.1

When testing QSG_VISUALIZE=overdraw on Windows Phone 8.1 (ANGLE D3D11), the following error is logged repeatedly and no rendering occurs:

"
QOpenGLShader::link: "Precisions for uniform tweak do not match between the vertex and fragment shader
"

Yet to check on other platforms with the same ANGLE build (desktop, WinRT PC) to see if the error exists there as well.