COUNTROWS with a slicer and treemap

Hello

I'm trying to create a report showing jobs raised by employees, but I'm having some issues with some measures I've created not showing correct results when clicking on the tree map.

The first image below, after clicking on the bar graph, shows the correct results. But when clicking on the tree map the figures change slightly - and it brings back slightly different results when clicking on each detail section for each employee.

Just wondering if anyone can explain why that would be happening and what I'm doing wrong? It seems to be linked to the Date Reported slicer, because when I change this to all dates the figures all come out okay.

Thanks in advance