ortho() function distorts mark symbols even when the option transform-shape:false is set

[RaulDurand]

While using the ortho() function, lines with marks that include the option transform-shape:false do not render properly resulting in distorted mark symbols.
Is there a specific configuration or additional setting required to prevent this distortion, or might this be a bug with how the ortho() function handles marks?

[johannes-wolf]

It is a bug/problem of how marks are handled in general. To really support not transforming them, we need to "tag" the shapes as marks/decoration an apply transformation later. #446 #329 #541