GAMEPLAY Tryndamere R bug

I main Tryndamere and have found that his R is actually bugged despite being quite simple. Many times on the brink of death (The most opportune time to activate it) I will attempt to use R and will still die, despite the animation along with the audio occuring, as well as the cooldown being activated... Meaning his R was consumed but you still die in that split second. This is extremely frustrating.

When your health is extremely low (enough to be one shot), activate his R to become invincible, have an enemy attack you in that split second and you will still die although activating the R.

I don't record and it'd be way to hard to screenshot but this has happened enough times that I am making a post about it, quite frequently. To fix this bug just decrease the time it takes to cast his R to 0 seconds, that way you can't die while still activating it.