Also consider the case of customer 19081. Even though it is only displayed in March, their Revenues YTD value is larger than Revenues. This is because the Revenues YTD measure considers the sum of previous months, even though Revenues may be lower than the threshold of 9,999.
Because the filter granularity is Year-Month-Customer, only the filtered combinations are also considered in the year total. This explains another unexpected result. The Revenues YTD computed in December is different from the one computed for the entire year – yet another unexpected behavior for a year-to-date calculation. At the month level, only customers with Revenues higher than 9,999 in December are considered, including all the months in their Revenues YTD calculation. However at the year level, all customers with revenue higher than 9,999 in at least one month are considered; their revenues for the entire year are summed to compute Revenues YTD regardless of the monthly filter applied to the Revenues measure.
Marco goes into detail regarding the nuances of filtering and also provides some good answers to common problems.