What strain are you using, and have you had this issue with hard candy from other people? I'm guessing this could either be a specific terpene, or there's something in your environment the plant is picking up.
If you're looking to get rid of most of the terpenes, try evaporating the ethanol the way I used to in a rice cooker. Boil the ethanol off, then do the decarb. Without oils to absorb the terpenes, it makes a rather 'flat' extraction.
You could also try water curing for a week, changing the water each day. This removes a significant number of terpenes.
Do you HEPA filter your grow air, or do you filter your extracts with a very fine filter?
What methods and input materials do you use to grow your cannabis? What is the environment like?
At least the feeling goes away once dissolved.