AnimationPlayer Onion Skinning is disabled due to corrupted rendering bug

[Gromph]

Godot version

v4.0.dev.20211015.official [f113dc9]

System information

Windows 10 21H1, Vulkan, Nvidia GTX 760 472.12

Issue description

Turning on Onion Skinning and moving the current track position results in flickering red with bits of garbage from the UI mirrored and upside down

I verified that Onion Skinning does work correctly on this computer with Godot Version 3.3.4 and 3.4 beta 6 using GLES 3

Steps to reproduce

1. Create new project using Vulkan Clustered or Vulkan Mobile
2. Create a 2D Scene
3. Add an AnimationPlayer
4. Create New Animation
5. Click Onion Skinning
6. Move Current track position

Minimal reproduction project

OnionSkinning.zip

[andersmmg]

Just a note, this issue persists in alpha 6.

[alex9099]

I can reproduce on alpha8, arch linux with nvidia 1060 (laptop)

this seems to happen as long as the current time/position on the play is not 0

[Ansraer]

Can reproduce this in alpha 10 on win 10 with an amd 6900xt.

[insomniacUNDERSCORElemon]

Seeing this in Beta 1. Aside from breaking the feature itself there is a fast flickering with the red, I am by no means a doctor but this may be a potential seizure risk.

So probably something that should be fixed ASAP.