Inaccurate radiation calculation

I tried a validation problem with fvDOM on axisymmetric case. The example case is attached.

Radiative analytical heat flux from "hot" wall comes out to 260.9 kW/m2.

Axisymmetric test case under-predicts the heat flux (15% error) (wedge patch)

Steps to reproduce:

Download the zip
Extract and execute Allrun (50 or 100 timestep entry is sufficient to analyze the issue)
Observe qr field on hot and cold patches in paraview

Is there a way to solve this problem?

Thanks in advance!