It maybe something I doing myself, but, the refresh option of group membership (KIX32 /F) only works once a day for me, so no matter how often you change group memberships, they will not be recognised until the next day.
I usually, whilst testing, add myself as an individual:
if lcase(@userid)="xxxx"
...do something interesting...
endif
Just to make sure the rest of the code actually performs as expected.