Quality difference Webtorrent vs. HLS

So i have two PT instances (both on PT 3.4.0, ffmpeg 4.2.4), one has WebTorrent enabled, one HLS.
I uploaded a video to both instances and there is is a noticeable difference in quality.
The video has mostly monochrome areas with small font letters (imagine UML diagrams).
Webtorrent is doing fine, the HLS version looks grainy/smeared - i was wondering if anybody else ever noticed something like that/what might cause it?
Unfortunately i can’t post the link to the HLS video because it’s in a restricted network. Please tell me if i can provide anything to help.