Smell it it will will smell moldy if it is. If you taste mold or anything feels off than I would say compost that batch. If it is fine then you can refrigerate the pickles. You will likely have to add a fresh bit of salt brine to make sure that they are fully submerged again.
Why do pickles have a strong, bitter taste? This happens when you use old spices, cook too long in vinegar, or you use too much spice. Using a salt substitute in place of Ball® Salt for Pickling & Preserving could be the problem. Salt substitutes contain potassium chloride, which is naturally bitter.