I have tried this file again, by saving as a v21 file - v22/RedSDK doesn't like my Nvidia Quadro graphics card.
And, I can now replicate the problem when running with RedSDK.
Now that I can see the problem, I have to say it looks very much like software related - i.e. RedSDK!
I appears to be connected to the distance the camera is away from each unwanted line.
Zooming in removes the lines but more slowly the greater the distance.
I know this is of little help, but, we'll just have to wait for the developers to improve things.
You can design without engineering, but you cannot engineer without design.
Using Win 10 with Designer 2016/2017 and TurboCAD Pro. Plat. 2018/2019 + Lightworks (64-bit versions) + AnimationLab 5.2.
Windows 10 Pro (1909) 64-bit