18 votesCraig commented
In a lot of scenarios, you can't erase highlighter stokes over pen stokes. I had the highlighter set to 8mm and the pen is set to 0.3mm I believe.
This should not be like this, since the highlighter stroke is much larger than the pen stroke and can be easily touched by the eraser without touching the underlying pen stroke.
26 votesCraig commented
I always use 0.3mm ink with pressure sensitivity enabled.
Sometimes getting to close to the screen with my pen will cause a very light pen mark over some important figure I have drawn. While in the app, this mark is practically unnoticeable, but when you generate a PDF this mark becomes a much thicker and intrusive stoke.
Trying to find and eliminate these accidental stokes is usually difficult.
It seems like you are missing PDF support for marks that are that this minuscule and then are up sizing them on export.