Are the walls around the tub cbu or drywall? Drywall should never be used in a wet area. Is that drywall mud or mortar? If mortar, your tub will likely be scratched cleaning off the excess. It should NOT be tight there, but there SHOULD be a vapor barrier installed behind it, lapped over the tiling flange. You might be able to use a topical waterproofing material, one is RedGard from Custom Building Products, or Hydroban.
If that's drywall mud, you've got a problem...well, even if it's thinset, you have a problem. Wait for one of the pros, but it sure looks pretty sloppy and not in accordance with general practice or manufacturer's instructions to me!