CA PPM 15.1 On Premise
On development env its working correctly
on Test and Production not.
result is multiplied with 365.
1.11.2016, 2.11.2016 dev=1 tst=366
1.11.2016, 3.11.2016 dev=2 tst=731
1.11.2016, 4.11.2016 dev=3 tst=1096
behavior on tst is number of days * 365 + 1
Same behavior is on all DateDiff attributes we have.
It seems related to the date formats,
i would say that Clarity is using the american yyyy-mm-dd and your dates are in dd-mm-yyyy.
Can you verify at oracle/sql server database level?