Yes, I can see the problem. I added ORG-25299 and we will fix for the next version. Do you have your LT code in an ogs file? The simplest fix is to detect LT code is executed in a file, instead of Script Window or Command Window and the wks.col.py$ line will not execute internal recalculation.
There is a simple workaround though, which you had implied, basically the Recalculate Operation needs to be setup successfully first, then changing in the proper order will work, see
wks.col2.script$="i=1;";//something to setup the operation
wks.col2.py$=
"def add1(a):
return [val+1 for val in a], [val+2 for val in a]
";
wks.col2.script$="col(B),col(C)=py.add1(col(A))";
CP
