Its harvestable, just have to wait until the drones all hatch and the empty cells get filled in with honey, that could take awhile though, as the queen may lay into the vacated cells once again. Or, if you're really impatient, you can just wait until all the drone brood on the honey frames are capped, then remove them to extract, just uncap the honey part and leave the drone cells capped, the honey will spin out and the drone brood will stay in the comb, it'll work.