I've only bought PFS one time but the contents were dry and the bags were stored indoors. It's possible the store either stored the bags outdoors or if the weather has been hot and humid in your area, you are just seeing condensation.
I would cut a small slit or hole in the bag and give it the sniff test. If it smells normal, just rinse and use as normal. If it smells off, tape over the slit or hole and return for another bag and check that one for the same conditions before buying.
I would cut a small slit or hole in the bag and give it the sniff test. If it smells normal, just rinse and use as normal. If it smells off, tape over the slit or hole and return for another bag and check that one for the same conditions before buying.