You might want to check the ingredients list on your sugar free maple syrup. just because something says it's sugar free unfortunately doesn't mean to say we can eat it because most of the time it will contain another sweetner which is just as harmful as sugar. Are you using the Queen brand sugar free maple syrup? I've checked on their website and here is the ingredients:
Water, Sorbitol, Vegetable Gum: Sodium Carboxymethyl Cellulose (466); Flavouring: Natural Maple Flavours; Salt, Acidity Regulator: Citric Acid; Colouring: Caramel Colour (150d); Preservatives: Potassium Sorbate (202), Sodium Benzoate (211); Sweetener: Sucralose.
On Davids list, Sorbitol is lised under bad, the sweetener sucralose is an artifical sweetner and is under your call. Probably best to avoid this as Sorbitol is the second in the ingredient list.