Canon 5D mark IV is a new camera which came out about Sept last year. As such the corrections for this camera's raw images probably has not been included in any of the updates.
A similar thing happened with the intro of the Canon 5D mark 2 some time back and there Photoshop could not open the raw files. So it is a case of the graphics programs having to keep up with the latest camera raw images.
I have a mark 3 and the raw images only appear normal from PSP X5 onwards. In X4, X3, X2 they are oversaturated and in 2 a terrible shade of saturated pink.
You could take out a ticket or use chat line to see when Corel is going to include the mark 4 in its update compatibility list.
Systems XP, Win7, Win 8.1,Win 10 14393.953