and Pale Moon do randomize/poison the canvas data canvas.poisondata (true/false, v25.6+):

about:config: canvas.poisondata default boolean false

That's even more dumb to have a switch for it and turn it off by default. Is there another switch to turn off audio fingerprinting and other fingerprints? /facepalm

I don't see any "bad request" error either on the site or in the dev tools. Maybe you have some extension or setting that's causing that, which of course is a signal to differentiate you from default pale moons.

and Pale Moon do randomize/poison the canvas data canvas.poisondata (true/false, v25.6+):

about:config: canvas.poisondata default boolean false

That's even more dumb to have a switch for it and turn it off by default. Is there another switch to turn off audio fingerprinting, another to make the screen size not easy to obtain by just rounding to standard sizes? /facepalm

I don't see any "bad request" error either on the site or in the dev tools. Maybe you have some extension or setting that's causing that, which of course is a signal to differentiate you from default pale moons.