System Information
Operating system: Windows-10-10.0.19041-SP0 64 Bits
Graphics card: GeForce RTX 2080 Ti/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 456.71

Blender Version
Broken: version: 2.93.0 Beta, branch: master, commit date: 2021-05-24 15:29, hash: rB1a69d491e57c
Worked: (newest version of Blender that worked as expected)

Short description of error
Blender draw some strange pattern when instancing a lot of instances with geometry node, looks like culling optimization but I heard it wasn't

see topic here https://devtalk.blender.org/t/geometry-node-and-viewport-culling/20565
"That looks more like a bug or a drawing artifact to me honestly. I’m not aware of any culling that would do that."
see gif in the topic
see blend file example

Exact steps for others to reproduce the error
Open the blend file and see the artifact

BLEND FILE
https://pasteall.org/blend/90eb1231a35e497bb529cdf59fea19ab

Artifact:

this one is quite small, sometimes it is quite heavy, as shown in the gif in the topic