Inconsistent data after refresh

[QS7]

Hello, I have a measure for which everytime I refresh the data it gives different results ( But the data in the database has not been touched so it should give me the same result ).
The measure concerned is : 

CALCULATE (
    COUNTROWS (
        FILTER(
            SUMMARIZE ( 'Sales', 'Sales'[Name_Surname_ID], "Agg", SUM ( [IS_Customer]) ), 
            [Agg] > 0
        )        
    )
)

 Do you have any idea on what can cause this issue ?
Thank you for help.

[QS7]

Hi @amitchandak ,here is a sample data from the table Sales : 

date					idSale	idOrder	Name_Surname_ID		IS_Customer	Group
2014-01-04 15:38:41.000	1111	555		SebastienVer		1			EU2014
2014-01-04 15:38:41.000	1111	555		SebastienVer		-1			EU2014
2014-01-04 15:38:41.000	1111	555		SebastienVer		1			EU2014
2014-01-09 16:36:22.000	1112	5551	veroniqueHoe		1			EU2014
2014-01-09 16:36:22.000	1112	5551	veroniqueHoe		-1			EU2014
2014-01-09 16:36:22.000	1112	5551	veroniqueHoe		1			EU2014
2014-03-21 14:01:22.647	1113	5552	CorinneSeres12123	0			EU2014
2015-01-28 14:19:21.000	1118	5556	SebastienVer		1			EU2015
2015-01-28 14:19:21.000	1118	5556	SebastienVer		-1			EU2015
2015-01-28 14:19:21.000	1118	5556	SebastienVer		1			EU2015
2015-06-07 19:51:21.433	1133	5566	andreJacques98421	0			EU2015

And this is the resulting output : 

Group	count_IsCustomer
EU2014	2
EU2015	1

[amitchandak]

@QS7 , Just check do you have any other column of measure as Agg.

Or change this name a bit and check

CALCULATE (
COUNTROWS (
FILTER(
SUMMARIZE ( 'Sales', 'Sales'[Name_Surname_ID], "_Agg", SUM ( [IS_Customer]) ),
[_Agg] > 0
)
)
)

OR

Can you share sample data and sample output in table format? Or a sample pbix after removing sensitive data.

[QS7]

The column IS_Customer is a Integer and come from the table Sales.
And the column Name_Surname_ID come from the table Sales aswell but it's a concatenation of 3 fields ( Name, Surname and ID ) in PowerQuery.

[amitchandak]

@QS7 , That is strange. What is data type of IS_Customer and it from table sales IS_Customer ?