I believe the problem is caused by the sweep not being united with itself, and not a tolerance issue as reported in the issue you linked. In fact, I'm not sure if anyone has created a ticket for this issue yet.
For example, the end face shown in the preview should not be there.
It works if the face is not over anything being cut, but completely fails, if the sweep is making a cut all of the way around, like in the file I posted.
industromatic wrote: ↑Fri Sep 08, 2017 1:20 am
Here is the file again in case you see anything else non-recommended to point out.
You may have to introduce some shape binders into the mix now that the cross coordinate system link prevention has been merged. This is what ickby said about it, if you are wondering the reasoning behind the restrictions.
The restrictions on links is kind of a feature. It creates some boundaries to what you can do, however, with this we ensure that all freecad document objects works like the user expects them to. So not a feature in a sense of new things, but a feature n the sense of keeping things working and logical.
It is generally now required to create a shape binder when you need to reference geometry in a different part or body. The shape binder will then correctly handle the different coordinate systems.
I find your construction method a bit odd, but not knowing your design intent, I can't really say if there is a better way. I mean I see box with radiused corners, a lip, and a couple studs, but I don't know what the most important parameters are and how much they should be able to be modified.
Thanks for sticking with it! I'm sure learning FreeCAD can be a frustrating experience, but the issues you find help make FreeCAD better.