After the initial "cure" the polymerization process continues at a slow rate for many days -- and sometimes months. It depends on the temperature, the thickness of the material, the composition of the materials, and a few other factors I haven't been able to figure out. (I call these "magic")

Varnish can take a while to get good and hard, too. My epoxy seemed harder a year after I built the boat than the first time I launched it. Think of it being like wine that improves with age.

Now be happy the stuff is still a bit soft and scrape off any runs while you can. When the finish is bone hard you'll need to go to with slower and dustier sanding to do the job.

PGJ