The only difference in these 2 formulas is at the end
GANZZAHL is german for INT and ODER is german for OR.
When I put these 2 formulas in separate cells they show correctly TRUE and FALSE. E.g. if I write in K5 '805' it should not work. With the first formula the data validation fires, in the second formula not. Putting the 2 formulas in separate cells both show FALSE.
Is there a character limit or something? The data validation dialogue doesn't show any error...