Good Morning and welcome! I am Dr. Loretta, a licensed veterinarian and I am happy to answer your question.
It does sound like Atticus has a digestive disturbance which may be an allergy ir it may be hereditary. If this soiling in the house seems like incontinence, I would worry about a neurologic issue that affects the anal sphincter so that Atticus cannot hold this in. This could be due to an unstable disc in his back that blocks some of the nerve supply allowing this fecal incontinence.
The best thing to do is to have your vet examine Atticus and run blood work as well as xrays to determine if there is a meidcal cause for this. In most cases, with dogs that are housetrained, the cause is medical and can be treated.
For now, give Atticus aspirin at 5 mg per pound every 12 hrs. If there is an unstable disc in his back, this will decrease the inflammation that may be blocking this nerve supply. Then feed Atticus the diet he is used to alog with Probiotics given daily ot help with digestion.
It is important that you have your vet examine Atticus...
Does that make sense to you?
Please let me know if you have ANY other questions. My goal is to give you 100% satisfaction and if you are not yet satisfied, please REPLY so I can clarify for you.
Sincerely, XXXXX XXXXX