Formulations change all the time. They don't have to list what the inactive ingredients are. It may not be the problem, but at this point we have to look at all the usual suspects. Foaming like you see is generally caused by a few different things. White water mold will have a scummy appearance, but it doesn't usually foam. If you have used an algaecide that may cause foaming. Sometimes additives to liquid bleach to prevent splashing or added fragrances will foam. Calcium, maybe, but it usually causes clouding more than foam. The last suspect is someone put something in the pool that doesn't belong there, such as soap. Do you notice any scent to the water? Soft water may foam as well. What is your calcium level?