Constraint and Modgen SKILL - resulting in incomplete modgen

I'm trying to use the code from this Cadence Solution ID: 20024536

; creating modgen group member list
d_cacheId = ciCacheGet( t_schLibName t_schCellName "layout" )
ld_instIds = d_cvLay~>instances
l_constMembers = nil
foreach( d_id ld_instIds
  if( d_id~>pin == nil then
    l_constMembers = cons( list( d_id~>name 'inst ) l_constMembers ) ) ; if
) ; foreach

; modgen constraint
d_constr = ciConCreate( d_cacheId 'modgen ?members ciExpandMembers( l_constMembers )
?params list( list( "numRows" 2 ) list( "numCols" 4 )
list("pattern" "custom ((A A A A) (B B B B)) ((R0 R90 R0 R90) (R0 MY R0 MY))") ) )

After this, I've added this line to auto-generate the modgen layout:

mgGen( d_cvLay d_constr )

The constraint and modgen are indeed getting generated, but the modgen is incomplete - It's created as two rows and four columns as mentioned in the constraint, but the pattern is not followed.

After this if I open the pattern editor manually and click apply, the modgen gets modified to the correct pattern - which means whatever constraint that is created is correct, but somehow the generated modgen group is incorrect.

Please help.

Thanks,
Leo