Yes, that's the problem.
The values coming from MonthYear field are: nov.-2017 and you are setting the variable to be Nov-2017.
I recommend you to format the MonthYear field in the script to be the same format you are doing it for the variable. That way the field is set to a proper Date format and the set analysis will work.
I would change the MonthYear you have in the script in Master Calendar to:
Dual(Month(TempDate)& '-' & Year(TempDate),MonthStart(TempDate)) As MonthYear
vCurrentMonthYear = Month(Today())& '-' & Year(Today());
I hope this helps,
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