(Heavy) Karthus Bug - Q does not deal damage if Karthus enters Death Defied in the casting time.

As a Karthus main, I noticed this bug and it is happening a few times every game I play him. (Missed 3 Kills because of it last game )

• I used Plague Grim Reaper Karthus Red, but I assume it has nothing to do with the skin. This is how it happens:
• Karthus casts Q - Lay Waste
• before it explodes, within the 0.5 seconds casting time, Karthus reaches 0 hp and Death Defied activates.
• the casted Lay Waste does not explode and does not deal damage.

This bug also happens in a similar way at the end of Death Defied, but not always.

• Karthus is defying death
• Karthus casts a Q - Lay Waste
• before it explodes, within the 0.5 seconds casting time, the duration of Death Defied ends.
• the casted Lay Waste does in some cases not explode and does not deal damage.

But wait, there's more!

The Q also contains a visual Bug:

• Karthus is defying death
• He casts a Q - Lay Waste on maximum range, with the cursor out of the maximum range.
• A Q - Lay Waste is being casted and explodes on maximum range in the desired direction.
• At the position of the mouse cursor, there appears a copy of Lay Waste's perimeter marking (the rotating circle that shows the explosion size)