This issue only affects iOS. I have no problems with ColorOverlay on macOS or Android.
When attempting to use the ColorOverlay Component, I'm presented with the following error in the Application Output:
"ShaderEffect: Failed to read :/qt-project.org/imports/QtGraphicalEffects/shaders/coloroverlay.frag"
The ColorOverlay is then ignored and the affected image remains in its original bitmap form. This appears to be a regression as compiling in Qt 5.8 works just fine.
I've attached a tiny example project which can be run on any platform to demonstrate that it only breaks on iOS.