I think Primal just increases your sensitivity to everything. It's like your senses have been dulled for so long in this puffy carb overload that, when they finally come out they just seem super sensitive. Really they are getting back to normal.
For instance lots of people have reported that they don't use as much salt as they used to just because they can really taste the flavors of the food and it doesn't need salt. Also people have reported getting more sensitive to alcohol. Plus latent sensitivities to things such as dairy and grains can become severe when you have really cleaned out your system for a while and then re-indulge.