Linux Mint - Gimp 2.10.14 perhaps.
I can not replicate that, at least not with a mouse ( a little closer with a graphics tablet but not with your brush settings)
You have a dynamic set pressure-size but with a mouse there is constant pressure, so it should have no effect. Set it back to dynamics off.
The brush size is 41, spacing 12 and the drawn line must only be 3 or 4 pixels. Beats me. Should be like the wide line. I can get a jittery line with a small brush size and a user dynamic but not your settings.
In case some unseen setting in place, you could try deleting the file devicerc in your Gimp user profile. It holds mouse/tablet settings. Gimp will make a new one if you change input device settings.
I can not replicate that, at least not with a mouse ( a little closer with a graphics tablet but not with your brush settings)
You have a dynamic set pressure-size but with a mouse there is constant pressure, so it should have no effect. Set it back to dynamics off.
The brush size is 41, spacing 12 and the drawn line must only be 3 or 4 pixels. Beats me. Should be like the wide line. I can get a jittery line with a small brush size and a user dynamic but not your settings.
In case some unseen setting in place, you could try deleting the file devicerc in your Gimp user profile. It holds mouse/tablet settings. Gimp will make a new one if you change input device settings.