Setup:

top triangle is the triangle made by pen+
bottom triangle is a mock-up of what should be drawn (made using a gradient in costume editor)
the triangle drawn with pen+ does not blend seemlessly with the bg most of the time
triangle does not blend in at all on a black background
Another issue i found was the triangle rendering weirdly when set at different opacity levels
Wavy effect when transparency is low
also happens like this
changing to a value above 100 also produces weird results