i don't use stabilizers as a preference (not a fan of slow strokes) for some reason this happens when i draw on magma specifically.
above: magma.com
below: a different drawing software
both with stabilizers at complete 0, both with the same canvas size... though this happens on smaller canvases too. this has been happening for a relatively long time now. I wasn't really able to capture it in the short recording but the site seems to slow down my cursor (while hovering) as well.
I'm not sure if it's an actual bug or just the way the website handles their brushes/brush engine, but it's a bit frustrating.