[GAMEPLAY] ULT Cooldown Bug for many champs

Sup summoners

There is a bug on cooldown reduction for many champs (I believe) in league. This bug has been here for a long time (first occurrence on me was S4)

This bug will not break your game, but it is actually pretty annoying when you find out you need to wait a lot longer to get your next ultimate.

=============================== So, what is the bug?

If you deploy your ult at the same time that you respawn from home, your spell cooldown will not benefit from your cooldown reduction as supposed. Instead, the cooldown will be the default cooldown of the current level of your ultimate.

For example. The cooldown of your ultimate in default (without any reduction) is 100s, and you have a cooldown reduction of 20%. My math teacher tells me that my cooldown should be 80s. However, with the bug, your ultimate will take a full 100s to reset.

I believe that this bug will only be activated within 0.5s (or shorter) after you respawn.

=============================== How to reproduce the bug?

0. Get your champion to LVL6 (Or you don't really have an ult to deploy.) 1.5. Get some cooldown reduction (Clearly you will find nothing different otherwise.)
1. Die
2. Fire your ult at the same time you respawn (NOTE: In order to have a better chance firing your ult at the right time, I recommend you pressing your R key rapidly when you are about to respawn.)
3. You will see the cooldown reduction is not applied.

Please note that this might take a few tries to success.

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The provided link is a youtube playlist that contains all the videos that shows the ult cooldown is impacted by the bug that ignores any cooldown reduction. I will keep this updated as long as I have time.

Currently confirmed champions that are impacted by the bug:

=============================== EDIT 1 (on 07/21): added to the list. Also, it seems that a champion is less likely to activate the bug if he/she/it has a longer channel time while using the ultimate. I assume that the cooldown starts to calculate after the ability is fired (completely channeled) and you have to make your ult run into the cooldown before the limited bug window runs out. (e.g. I have never reproduced this bug successfully on annie and lux.)