Its not really a bug.
strange problem of the behavior of the open tube cover. so I still work in smooth shading which is important for the future. so we have the possibility to make a tube with a hole but
what is strange is that when we pierce the tube the lid of it seems softened or already subdivided I mean quin has a rounded edge rather than a sharp stop yet if we do not perceive the tube then the stop remains very clean . I tried with
different parameters but you have to go too high in resolution to keep the sharp edge. it’s weird.