Blanks shown in table even though filtered out on the page

[Jebilaya]

I have a calculated column called Actual Dwell which has the following DAX

ActualDwell = if(isblank('Microlise Files'[Planned departure]),Blank(),datediff('Microlise Files'[Actual Arrival],'Microlise Files'[Actual departure],minute))

When I put the data into a table though that has blanks filtered out on the page filter and the table acknowledges it should only return 0 - 36 values it is still showing the blanks.  Why is this?  The DAX is telling it that it is a blank so there's no spaces or anything in the data.

[Jebilaya · Accepted solution]

Fixed by selecting is not blank in visualisation filter