(Epilepsy Warning) Random black Screenflashes with GLES3 and dense Meshes with Blendshapes

[smix8]

Godot version:
v3.2.4.rc1

OS/device including version:
Win 10 64x
GTX980TI or RTX3070

Issue description:
I get random but very steady (every few seconds) black screenflashes that increase in frequency the more the Godot graphic settings are turned up. It happens only with GLES3 and only when very dense meshes with blendshapes are included in the scene

e.g. all characters in the sample gif below, a little zoomed in but otherwise at max Godot graphic settings.

On lowest graphic settings it flashes less frequent but then it looks like extreme-reverse auto exposure behaviour. Instead of blinding white light that gets darker, I get very dark or complete black screen for a frame that returns to normal over 1-2 seconds.

I first thought it must be auto exposure so I made sure it was turned off. Didn't change anything.
Next I turned off ScreenSpace Reflections. The problem happend considerable less but still frequently enough.
Next is set the entire set of graphics quality options of Godot to off or super-low and now I have this random fade to black every few seconds.

So my question is ... what could cause such behaviour, especially that lower graphics settings stretch the timewindow, and/or how can I narrow it down to create a minimal reproduction project?

Steps to reproduce:
Not sure but seems ... use GLES3 with a 3D scene that included dense meshes with blendshapes at max Godot graphics ssettings.

Minimal reproduction project:
see my question how I can narrow it down to create a minimal reproduction project (without sharing the giantsized project)

[Calinou]

and/or how can I narrow it down to create a minimal reproduction project?

Maybe create a dense subdivided cube/sphere that's rigged and linked to a blendshape.

[JohnGabrielUK]

I've had a few people report this on one of my games, Pulse Limited. It only seems to affect people running NVIDIA cards. The problem seemed to start on the doors, and then spread elsewhere through screen space reflections - disabling those would cause the glitches to just be limited to the edges of the doors. Disabling the door's normal map fixed the problem. I have a couple of theories on why this might be the case:

• The way the normal map is projected onto the door (I used "project from view") - so on the front side, it's fine, but on the reverse the
• The way the normal map is interacting with the level's baked light map (the glitches only occur when the door is open)

[smix8]

Issue became worse with recent 3.3 RC6 release.

Now instead of flickering or fade from black entire 3D scene turns black for seconds.

I was unable to pin it down to a single testmesh. Everytime I isolate a mesh the issue doesn't show but as soon as I combine multiple of them to create a heavy 3D scene it goes off.

[Calinou]

Seeing @JohnGabrielUK's comment, I wonder if #46800 would solve this.

[Calinou]

@smix8 Can you still reproduce the issue on 3.3.4 or 3.4 beta6?

[smix8]

@Calinou
I was unable to reproduce the issue, reason why i closed it.