Solenoid should set number of coordinates in r, z on the field map using PropertyInts NumberOfRCoords, NumberOfZCoords. However, it takes both these parameters from NumberOfRCoords. Default is loaded correctly (from datacards).

Module CoilWriter
{
    Volume Tube
    Dimensions 430. 530. $coil_length mm
    Position -$r_c*(2*cos($n_s*$dq)-2) 0.0 -10.0+$cell_length*@RepeatNumber m
    PropertyString FieldType        Solenoid
    PropertyString FileName         linac.fld
    PropertyString FieldMapMode     Write
    PropertyDouble CurrentDensity   1.
    PropertyDouble Length           360.
    PropertyDouble Thickness        100.
    PropertyDouble InnerRadius      430.
    PropertyDouble ScaleFactor      $str_coil_J

PropertyDouble ZExtentFactor    $z_extent
    PropertyDouble RExtentFactor    3.01
    PropertyInt    NumberOfZCoords  $n_z
    PropertyInt    NumberOfRCoords  $n_r

PropertyDouble RedColour        1.
    PropertyDouble BlueColour        1.

PropertyBool   RepeatModule2    true
    PropertyInt    NumberOfRepeats  $n_s*2
  }