it will set up eventually if the mix was reasonably close. Give it 24 hours before scraping. Humidity and temperature can do all kinds of things to cure time. 2 hour or longer cure time epoxies are most affected.

If the epoxy starts to get stiff but doesn't seem to quit being tacky, a thinned application of another layer will often kick it off the rest of the way. (only after waiting, and being certain its holding the load, just not tack free.)

After waiting, if its not stiffening up on its own... you will have to go ahead and scrape, but its a bad deal, because there will be "nevercured" epoxy down in the wood grain, where some of the strength of the bond is supposed to be.