Inaccurate stroke expansion with pressure curve applied to stroke

[Balakov]

Hi, I've read about problems with expand stroke before, but this is the first time I've actually encountered one myself. Super simple repro - create a circle with a thick stroke that has a linear 0-100% pressure curve applied. The expanded stroke is all wobbly. I also found that you start to get some bizarre buzzsaw strokes as the circle gets smaller, I assume due to losing precision. Expanding that stroke that makes a big mess too. Screenshots with settings attached. This is in Designer 1.8.5.703.

Thanks!

[Sean P]

Thanks for this - I'll pass it on to development.

The buzz saw effect you're seeing is being caused where the stroke size is far too big for the object and begins to intersect with itself. I'll also get this passed on.

[Balakov]

Thanks, Sean!

[loukash]

@Sean P, a similar (same?) issue when using the stroke pressure to mimic a live "roughen" effect.
What looks good "on screen" goes full havoc when expanded or exported for print to PDF.
The top object is a simple stroke, bottom object the same stroke expanded. The more compressed the spikes are, the weirder it gets:

 

Somewhat related UI issue:
The "Swap arrow head with tail" button is blank on Light UI.

Affinity 1.9.1, El Capitan, MacBook Pro 9,1