BIP report Pivot filter not functioning as expected

Summary:

Running an online layout for a pivot date from a data model doesn't properly filter null dates

Content (please ensure you mask any confidential information):

For the below you can see that the BCSTARTDATE field is filtered for 'IS NOT NULL' - but when I run the report it is not filtering out when this field does not have a date.

The field BCSTARTDATE is a date field in the data model. I have tried even modifying my data model such that nvl(BCSTARTDATE, null) to force a null value if there is some space or something, but the pivot still does not recognize the null for filtering.