I’ve used 3 different tokina 10-17 lenses over >10 years with a Nikon D90, D7100 and D7200 and have had exactly the same experience. When using an auto exposure mode, they invariably overexpose by 2 to 3 stops. I’ve accepted this as an issue with the Nikon metering system, and have learned to compensate whenever using an auto exposure mode, e.g. shutter priority for whales. When shooting in full manual mode for most diving with strobes, the problem disappears. It doesn’t bother me anymore and has become a normal part of my dive planning.