Yes, I bought some cartridges some time ago for a trip and they were supposed to be THC but it turned out they were HHC.
I must admit they do the job and I have not had any unpleasant effects ,I have found that many prefer it to THC for the low potency of the high but I would never knowingly buy it. Too little information and almost no certain study on long term effects, it doesn't seem like a really reliable product to me and it is always semi synthetic.
Many are also making sprayed flower and hash mixed with HHC but I get sick just thinking about it.