The tear could be inside the roll fold and because its up against itself (rubber) the leak will not be noticeable. Don't let this fool you as the leak is very minute. If the compressor keeps having to lift the vehicle every other day the pump may burn out and those go for around $500 plus the bags which ARE bad. Change the bags and you'll be fine.
The soapy water check should be inside the back under the spare. If its all clear there it's the bags.