Slow drying can also be attributed to painting coats on too quickly-maybe the primer or the paint. If one of the coats was not dry, or at least the time the mfr recommends, it could be trapping moisture. This surface will eventually dry out but you would be better offf not trying to hurry it up, you may cause it to wrinkle. I would leave it wherever it is, wait a month. You should not have any problems after that.
Barring an application error, the batch or custom mix could be bad. If it matches the color you wanted, this is probably not the case.