Properly mixed, Etex should set in 8 hours, and be harder after a couple of days.
My guess is the epoxy is too thin, or not there at all, on the part you can scratch.
If you are hanging the jigheads by the hookeye to cure, and not rotating them, the Etex is probably flowing down until it's super thin on the hookeye area.
I've always had to rotate anything I coated with Etex, because it takes 8 hours+- to set. And I always use at least 2 coats.
You might have better luck with D2T. It is more brittle, but it sets faster, so you don't have to rotate the lure/jig as long.
If you want to keep using Etex, try double coating the jigheads, and hanging them from the opposite end the second time.
Or use a lure turner for 8 hours.