Different values on bar chart, when clicking on a specific bar

[Applicable88]

Hello,

normally you will see the count, sum etc. as small number within the bar chart like this: 

As you see there is for week a time sum up of 55,37h.

When I'm clicking on it I get this:

Now I have 57,89h. Does someone know why I suddenly get another value of time just by clicking on it?

Thank you in advance.

Best.

[lironbaram]

Hi,
usually it's because of your expression, what expression do you use in the chart?