ERROR: The given mesh is not closed!

[quiet-ranger]

Describe the bug
I get this error with a very simple polyhedron with 5 faces only and I am not sure how to fix it.

To Reproduce
Steps to reproduce the behavior:

1. Create a new file with the following contents:

module sample() {
    polyhedron(
        points=[
          [0,0,0],[0,4,0],[4,0,0],[0,0,10],[0,4,10],[4,0,10]
        ],
        faces=[[0,1,2],[3,4,5],[1,4,5,2],[0,1,4,3],[0,3,5,2]
      ]
    );
}

sample();

2. Save the file
3. Press F6 to Render
4. From menu select Design / Check Validity
5. See error

Expected behavior
A more informative error of what exactly is wrong with the model

Code reproducing the issue
N/A

Screenshots
N/A

Environment and Version info (please complete the following information):

• OS: Linux Mint 21.3
• System: PC 64-bit
• OpenSCAD Version 2021.01 installed via flatpak install openscad

Library & Graphics card information
N/A

Additional context
N/A

[UBaer21]

try faces=[ [0,2,1],[3,4,5],[2,5,4,1],[0,1,4,3],[0,3,5,2] ]
With F12 you can see faces with wrong normal

more here https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Primitive_Solids#Mis-ordered_faces