Protest pooping?

[SamDog]

I have a four year old white shepherd dog. He is totally house broken. We got a new puppy six weeks ago. She never poops inside. Sometimes has a pee accident. Sam the adult dog has pooped in the house two times over the past couple of weeks. It is on a slate floor that has been washed and sprayed with Febreeze between poops, but it was roughly in the same spot.
The puppy follows him and is sometimes a pest. They do play and seem to have fun most of the time. Sam is a very gentle dog who rarely growls or snaps at her. He sometimes just wants to avoid her.
I am wondering if Sam is doing this because he is disoriented, or jealous. Have you ever heard of this type of inappropriate defecation when a new pet is brought into the home ?
Should I try to 'defend' Sam and separate them if it seems like he needs to get away from Mo the new pup ?
Any help will be greatly appreciated.