I noticed when updating segments at runtime, their thickness doubled.
After looking into the Segment.as code i observed that in the constructor it states _thickness = thickness *.5; while in the updateSegment method it states _thickness = thickness;

So now i wonder, is the thickness halved on creation of the segment for a position offset or has it another purpose? I presume it should be halved in the updateSegment method as well?

This is a known issue. It’s on the todo and should be fixed for 4.1.