Pixelated icons

[garfberg]

Hi,

Mapbox-gl-native version: 5.0.2
Platform: Debian Buster AMD64
Kernel: Linux map3 4.19.0-11-cloud-amd64 #1 SMP Debian 4.19.146-1 (2020-09-17) x86_64 GNU/Linux
xvfb: 2:1.20.4-1+deb10u1
GPU: NVIDIA Corporation GP104 [GeForce GTX 1070] (rev a1) with driver NVIDIA-Linux-x86_64-440.64

I am facing a problem with symbols which are randomly pixelated when generating tiles as png rasters.
I tested it under Linux with software frame buffer (xvfb) or GPU (nvidia gtx 1070) via Xorg.
This is more visible when using software rendering than the gpu card.

It looks like the problem described here: Fix pixelated icons #7302

Here is a screenshot of rendering done with xvfb:

On the first map, 256x256 with scale set to 1, the symbols are pixelated.
On the second map, 256x256 with scale set to 2, the symbols are ok (but blurred as use the same sprite for both 1x and 2x)
On the third map, 512x512 with scale set to 1, the symbols are pixelated.

The sprite altas contains only integer offsets with pixel ratio to 1.
Example:
"museum": {
"width": 23,
"height": 32,
"x": 457,
"y": 32,
"pixelRatio": 1,
"visible": true
}

I also checked the coordinates of the symbols and it looks good.
Example:
"coordinates":[2.34634,48.85602]

Is there something I missed ?
Thanks.