Hi @Mingus81
I might have exactly the same issue as yours! I just assembled my setup two days ago and I'm not sure if I used the right screws.. I just took the longest ones (long on both sides) but I suppose as per your last message that you probably used these ones too and changed for shorter ones?
I have the same specs as yours, i7-9700K a ROG Strix Z390-F and the H100i Platinum..
This would help me a lot!
Thanks