[Gameplay] Morgana Ult on CD without showing CD timer

This happened in an Aram normal game. Morgana ultimate was supposed to have a short animation with effect sound before dealing damage to enemies within the circle. In my case I died during the short animation effect without dealing any damage, and I checked on the ult icon, which said the skill was still up. I haven't thought about it and walked into the next teamfight trying to do a 5-men ult and it failed. I pressed R 4 times before I almost died but there was no damage, no animation, and no cooldown timer ticking on the skill icon. I waited for one more teamfight and tried, where it failed again.

Since I haven't been counting time for my ult, I would say it's approximately the cooldown time for the ult when I experimented on the third teamfight and succeeded. I am not sure if it is repeatable since it is rarely seen a Morgana died before her initial ult damage was actually done.

Steps I could think of to replicate this issue

1. Go low on health with Morgana
2. Ult at a precisely timed killing strike 2a. Should have heard the ult effect sound 2b. Should not have seen the ult animation

This results in ult going into cd without showing the cd timer, which would mislead the player into believing the skill was up - and totally ruin a teamfight. I believe there was a post about Kennen having a similar issue. The ult might be disabled as in the Kennen issue and re-enabled after I died in the disabled state too.