I call them niccups!

It means your throat and esophagus are getting too much topical nicotine. Its a typical smooth muscle response. 24 mg is a relatively high level, and you may be getting drops of juice in the mouth, or just holding the vapor in the throat. I get them sometimes with higher nic levels, but more often from nic gum or lozenges (do not chew the lozenges! 8-o). Never got them from analogs, since the oral nic absorption is much lower...it mostly goes to the lungs, riding on smoke particles.
Drink some water and they will probably pass as the nic is flushed out. A trick I know to get rid of hiccups that works 95% of the time with me is to fill a very large glass with water, like a liter, empty your lungs of air, and drink as much of that glass as you can without breathing. If you start to go into lung fits while doing it, all the better. They are almost always gone afterwards. Normal hiccups are a diaphragm spasm. But niccups generally just need a drink of water to flush it out. And yes, niccups are not like regular ones. They are higher up, and either one big one, with saliva flushing the nic out, or many rapid ones until the nic is gone.
Its true that hiccups can indicate several more severe problems, but as they say in medicine, if you hear hoof beats think horse, not zebra. The most likely cause here is too much topical nic.