wrong returned data when combining tables in a measure

Hi,bvdm1980 

Here are our solutions based on our understanding of your needs:
1.First I have created the following table and the column names and data are the data you have given:

2.I created the following table link:

3. Below are the measure I've created for your needs:

urchase order result = 
CALCULATE(
    SUM(budget[Budget amount])-SUM('detail'[Purchase order line amount]) - MAX('detail'[Risk reservation]),
   FILTER('order', 'order'[stauts] = "approved"))

4.Here's my final result, which I hope meets your requirements.

5.If the above options don't work, you can use the Allselected() function or the All() function in the FILTER() function:

FILTER(ALLSELECTED('order'), 'order'[stauts] = "approved"))

FILTER(ALL ('order'), 'order'[stauts] = "approved"))

The following is the relevant documentation:

ALLSELECTED function (DAX) - DAX | Microsoft Learn

ALL function (DAX) - DAX | Microsoft Learn
Or check if your table relationships are affecting your results, and the meassure you are quoting.

Can you share sample data and sample output in tabular format if I am misunderstanding? Or a sample pbix after removing sensitive data. We can better understand the problem and help you.
Please find the attached pbix relevant to the case.

Best Regards,

Leroy Lu

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