Prebuilt MinGW Qt binaries do not contain d3dcompiler_47.dll. This dll is required by Angle. Lack of this file can cause problems with windeployqt.exe, since it will try to find the dll from system directories, and that dll may not be compatible with other windows versions (Windows 7 <
> 8 <> 10).
Visual Studio prebuilt binaries contain this file.
Older Qt versions also do not include this file for mingw packages.