It is a bug (well, a limitation), but AFAIR from my own designs, it generally only affects the low-precision, "fast" preview; in the final calculation it won't be an issue.
Nevertheless it is one of the things that is annoying as hell with the OpenSCAD previewer; constantly having to over-join to avoid it just makes the code more painful.
Coplanarity is generally a challenge in fast CAD previews.
It is a bug (well, a limitation), but AFAIR from my own designs, it generally only affects the low-precision, "fast" preview; in the final calculation it won't be an issue.
Nevertheless it is one of the things that is annoying as hell with the OpenSCAD previewer; constantly having to over-join to avoid it just makes the code more painful.
Coplanarity is generally a challenge in fast CAD previews.