Why do I get a meshing error in GMSH when using boolean intersection?

Question

Good morning all,

I am trying to build a piece for a homework in GMSH. The goal is to study default impacts in pieces on heat transfers. We were asked to design a rectangular parallelepiped with a hole in the middle. Our approach was to first make the rectangular piece and then, using Boolean functions, to remove the cylinder representing the hole. We managed to get the correct geometry but the meshing process raises the following errors

Warning : MakeMeshConformal: wrong mesh topology

which is followed by

Error : Could not find extruded vertex (0.168704694055762, 0.1734549444740409, 0.04571428571428571)

Error : Could not find extruded vertex (0.168704694055762, 0.1734549444740409, 0.04714285714285715)

Error : Could not find extruded vertex (0.168704694055762, 0.1734549444740409, 0.04714285714285715)

Error : Could not find extruded vertex (0.168704694055762, 0.1734549444740409, 0.04857142857142857)

...

Those vertexes are located above the hole, in the remaining material of the cuboid. I do not understand why those vertexes don't exist as the boolean function did not impact that part of the piece.

Please find our code below:

// Gmsh project created on Wed Feb 14 10:32:40 2024
SetFactory("OpenCASCADE");
//+
Point(1) = {0, 0, 0, 0.01};
//+
Point(2) = {0, 0.30, 0, 0.01};
//+
Point(3) = {0.60, 0.30, 0, 0.01};
//+
Point(4) = {0.60, 0, 0, 0.01};

//+
Line(1) = {1, 2};
//+
Line(2) = {2, 3};
//+
Line(3) = {3, 4};
//+
Line(4) = {4, 1};
//+
Curve Loop(1) = {1, 2, 3, 4};
//+
Plane Surface(1) = {1};
//+
Extrude {0, 0, 0.05} {
  Surface{1}; Layers {35}; Recombine;
}
//+
Circle(13) = {0.15, 0.15, 0, 0.03, 0, 2*Pi};
//+
Curve Loop(7) = {13};
//+
Surface(7) = {7};
//+
Extrude {0, 0, 0.04} {
  Surface{7}; Layers {28}; Recombine;
}
//+
BooleanDifference{Volume{1}; Delete;}{Volume{2}; Delete;}
//+
Physical Surface(28) = {13};
//+
Physical Surface(29) = {14};
//+
Physical Surface(30) = {9};
//+
Physical Surface(31) = {8};
//+
Physical Surface(32) = {10, 12, 15, 11};
//+
Physical Volume(33) = {1};

We tried to change the physical group but it didn't have any effect. I am convinced that the error is raised after the Boolean function but I do not understand what could be changed to resolve that issue. I am still convinced that the boolean function is the correct approach for such problem and I really want to understand why the meshing process fails.

Please find attached several picture of the piece we want to design and the geometry we got.

Thank you for your time