Will belt case be OK in salt water?

Will Aquapac Belt Case 848 leak if exposed to salt water for more than 30 minutes? Will water leak through the bag at all if submerged in water? Im not taking about a few splashes, I’m talking about full on snorkelling. Thank you for taking the time to read my questions.

The belt case is tested and OK for prolonged use in water, so snorkelling is fine.