I have found the same thing!
i ended up with a charming spray of poo on my leg
I was wondering if we may have too much pressure in the pipe?
But yes it is a pain and i am in a similar situation and yes it seems a bit gross and im not sure if thats how it should work. How do you stop the spray going everywhere with poo in it!
Im sorry im not much help but just wanted to say i have the same problem.