Why is there moisture in some cured meats?

Cut products (e.g. slices) and, in general, products with one or more cuts on their surface may tend to develop some moisture. This is expected and as long as these fluids are clear it is not an indication of poor product quality.
However, you should be careful:
If the fluids in the packaging are not clear but slimy and have an acidic smell, this is a sign of microbial spoilage of the product. This can happen if:
a) Your refrigerator has not been set on a temperature that is low enough (0- 40C).
b) You have not followed correct hygiene practices (clean fridge, clean hands, proper storage of product to avoid exposure etc).