Lag Spike Right Before and During Death

This usually happens when I am going into a risky situation, preparing to use flash or another escape. I get stunned or snared and I am pressing flash or other escape multiple times. The enemy stun is worn off but the whole game screen 'freezes'/lag spikes' for about 1-2 seconds during which I had plenty of time to flash out but as soon as the lag wears off I'm dead and flash is never triggered.

If flash actually triggered during this time (but I still died), I wouldn't consider this a bug. But flash/other skills for escape are not triggered at all during this 'lag spike' duration and usually results in certain death.

My ping in LoL is consistently 20-40 ms at the most. This bug has happened since the first time I played a couple years ago, across 3 different computers. It's very rare though only happening maybe one death per every 4-5 games, but it is noticeable enough that I remember it. Other than this lag spike issue, I've never had any lag whatsoever in this game.