MAX return wrong results

Hi, Analitika 

Based on your description, I created data to reproduce your scenario. The pbix file is attached in the end.

Table1:

You may create two measures as below.

TotalSumByOpNr = 
var tab = 
SUMMARIZE(
    Table1,
    Table1[ApNr],
    "Result1",
    var _opnr = SELECTEDVALUE(Table1[OpNr])
    return
    CALCULATE(
        SUM(Table1[Sum]),
        FILTER(
            ALL(Table1),
            Table1[OpNr]=_opnr
        )
    )
)
return
MAXX(
    tab,
    [Result1]
)

MaxDate = 
var tab = 
SUMMARIZE(
    Table1,
    Table1[ApNr],
    "Result2",
    var _opnr = SELECTEDVALUE(Table1[OpNr])
    return
    CALCULATE(
        MAX(Table1[Date]),
        FILTER(
            ALL(Table1),
            Table1[OpNr]=_opnr
        )
    )
)
return
IF(
    ISFILTERED(Table1[ApNr]),
    MAXX(
        tab,
        [Result2]
    )
)

Result:

Best Regards

Allan

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