evdev input doesnt work right with several modifiers

When using evdevKeyboard, which is mandatory when using eglfs, it seems that modifiers are not handled properly.

If i press Ctrl-D -> everything is fine
If I press Shift-D -> everuthing is fine
If i press Ctrl-Shift-D -> then i only get Ctrl-D in the QKeyEvent.

I enabled console log output and qt.qpa.input framework logging and here is what i found :

qt.qpa.input.keymap: Processing key event: keycode= 32, modifiers=05 pressed=0, autorepeat=0 | plain=246, withmod=251, size=612
qt.qpa.input.keymap: Processing: uni=0064, qt=00000044, qtmod=04000000
qt.qpa.input.keymap: Processing key event: keycode= 32, modifiers=05 pressed=1, autorepeat=0 | plain=246, withmod=251, size=612
qt.qpa.input.keymap: Processing: uni=0064, qt=00000044, qtmod=0400000

For the record, modifiers=05 means Ctrl & shift modifiers, which means that libevdev gets the right input.
But qtmod=0400000 means only Ctrl Modifier, which is wrong.

You will find attached a small sample that just prints out the KeySequence to console.