I have another achievement that is stuck and bugged in my tracker. I think it was the Belsavis Datacron Master achievement (it could have been Explorer of Belsavis). After I completed, the achievement is listed as -2698.505859375. When I click on it in the tracker, it takes me to my list of recently completed achievements. The only one on the top four that I recently completed and tracked was the Belsavis Datacron Master achievement. Please let me know if you need more information (I know which achievements I tracked, I just found the tracker recently so I only have a few).