Hm, I am having a blackout:

Why is this function not deterministic?!?

CREATE FUNCTION dbo.fnDateAdd()

RETURNS int

AS

BEGIN

RETURN 0

END

GO

Do I need to have any special session settings enabled?

SELECT objectpropertyex(object_id('dbo.fnDateAdd'), N'IsDeterministic')

returns 0.

I am stuck... 🙁

Btw: I prefer "wrong" questions with discussions that start your brain on a topic over questions where I just get my points.