I expect this is related with depth management. But depth management is between several "max" objects, like 2 jit.gl.mesh. How to manage this with several objects in one jit.gl.mesh ? Removing depth_write or depth_enable will messed up objects in different Z position in one jit.gl.mesh.
(Here an example with a background quad, and 2 quads at the same coordinates, in the foreground)