Sorry SE, but endgame won't work if you don't fix something.

[Ushio]

Sometimes I wonder if the red circle (or whatever) is just appearing late on my screen, because it seems like if I'm already in it and take a quick look at the casting bar...

Thanks for your quick reply
Seems you're living in the US and playing in NADC so I assume there's no serious lag problem. I pretty much invested on desktop PC so I guess I don't have hardware issues. How about your spec of PC?

It's said that the timing to decide whether you take the AoE hit or not is right on when the red disappears.
Considering the micro second lag(somehow no matter where you are), you can say it happens right before the red disappears.

In other words, you can get back to the red as soon as it disappears without taking any hit, even it looks you're totally cooked lol
If there's no problem with your PC, you can check if it's really so for you next time.

P.S. Try to run first whatever you do as soon as you see the red.