I think it could be a sign that your pouchitis is not as under control as you think, based on my own past history. Have you been scoped recently? The only suggestion I would make, beyond effective treatments for pouchitis like antibiotics and biologics, is to try an anti-spasmodic in case the issue is being caused by a spasmodic pouch. I actually think it's more likely pouchitis, as nighttime leakage was always a sign of slippage for me.