Measure not displayed correctly

Hello everyone!

I applied the following measure to my matrix visual:

Ngroup1 = SUMX (
    GROUPBY ( 'Sheet1', 'Sheet1'[Fiscal year], 'Sheet1'[Obligation type] ),
    [Group 1]
)

Ngroup2 = SUMX (
    GROUPBY ( 'Sheet1', 'Sheet1'[Fiscal year], 'Sheet1'[Obligation type] ),
    [Group 2]
)

Ngroup3 = SUMX (
    GROUPBY ( 'Sheet1', 'Sheet1'[Fiscal year], 'Sheet1'[Obligation type] ),
    [Group 3]
)

When I checked my visuals, I noted there are rows in which the measure seems to not work correctly:

Kindly advise on this matter - why it happens and any way to fix it.

Best regards,

Bona