Harvest lockup is a feature that we have inherited from PantherSwap. Basically, it means that farming rewards cannot be immediately harvested, instead user can only harvest rewards every harvest interval. See information below for the example. This mechanisms was designed to prevent farming arbitrage bots from constantly harvesting and dumping.
User deposits 100 SDUMP tokens in the pool with 2hours harvest interval. After the deposit is made the user will not be able to harvest their rewards for another 2 hours. Once that time has passed user will be able to harvest again but each subsequent harvest will reset the counter to the 2hours again.