Why there is no srcset on live site?

What can interfere with perfect images plugin output of srcset?

On my local version, everything is fine SEE HERE, images are retina. I upload the complete site as it is to server, and there is no srcset, SEE HERE.

I’ve checked all settings, nothing was lost in upload, site is identical, but some images are not retina anymore (some are working fine, as you can see in both images code… I didn’t find the pattern, it just looks random). I also regenerated all images on the server, nothing changed.

Are there settings outside wordpress that I need to check? Server settings? Php version? (upgraded both to 8.1 now, still the same). What am I missing?