Residual foliage glow after a light flash

ENVIRONMENT: I have created a night scene with storm weather and lightnings. Those thunderbolts emmit realistic light flashes. I used UltraDynamicSky for weather and lighting of my scene. Lightningswere created also with UDS.

PROBLEM: After those flashes occur foliage (grass from Quixel) has residual glow for 4-5 seconds. See it here: Foliage glow bug - YouTube

MY THEORY: Is it connected to the fact that grass material has translucency strenght 0,7 and translucency desaturation 0,95 by default?

I would be super grateful for help! I’m new to Unreal. :smiley:

Lumen Lighting Update Speed

Lumen uses a number of caches to achieve real-time performance. While local lighting changes propagate quickly, global lighting changes, like disabling the Sun, can take multiple seconds to propagate. Projects can use the Lumen Scene Lighting Update Speed and Final Gather Lighting Update Speed controls in the Post Process Volume to work around this delay at the cost of increased GPU cost.

Thank you for your suggestion! But I have maxed out those two (it seems, that 4 is the maximum value for both) and the only change is that the duration of that glow have reduced from 4-5 seconds to 2-3 seconds. Changing Lumen Scene Lighting Update Speed to 10, for example, doesn’t give any effect compared to 4.