If you retrieve NaN rhos_* for Landsat or Sentinel-2 (in either the L2R or L2W outputs) this is caused by a high aerosol optical depth value. For these sensors the LUTs are reduced in size when they are loaded, by subsetting the view zenith angles and aerosol optical depth. If the estimated aerosol optical depth value for the current scene is above the subsetting threshold value, NaNs are returned from the LUT that will cause NaNs in the rhos_* outputs.
This issue can be resolved by disabling the LUT subsetting:
If you have NaN values in other datasets, but valid rhos_*, the cause
lies elsewhere.
Quinten