Every qt3d example compiled fine, but when run they crash. The OpenGL programs, though, run fine.

The error message:

Failed to link shader program: ERROR:OPTIMIZER-3 (fragment shader,
line 41) Support for for loops is restricted : right side of
condition expression must be constant
Segmentation fault

This error occurred with the default GL driver.

When using the special GL (VC4) drivers in software and hardware modes, which are installed with the raspi-config program, they both have the same error: "failed to add service - already in use?"
and when these (VC4) drivers were used, all QT programs, OpenGl based on non OpenGL based, have the same error.

Wouldn't help to attach libraries and program as all the libraries add up to more than your allowed 10.00 MB size.