CD reduction was not considered while casting Karthus Ulti
I was playing ARAM with Karthus and had 20% CD reduction. I was casting Karthus' ulti before and the CD reduction was calculated correctly. But once I casted Karthus' ulti directly after respawning (spaming R), so that it is casted as soon as possible. It was a lvl 3 ulti and the colddown timer was set to 160 seconds and not the 128 seconds.