Yep, since your daughter probably has a loop ileo in readiness for her j pouch, it's completely normal. Stool from the bag can get into the 'non-working' stoma aka mucous fistula stoma and out via rectum and anus. Scary if you're not told it can happen, but completely harmless.
I have had an ileostomy for 32 years now due to UC.
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