I haven’t experienced this, but several people have posted on the forums recently that the bite valve on the bottom of the resin cartridge was not split properly or at all from the factory. Read about it here. I would advise you to contact FL support as they do want to know about faulty bite valves…if this is indeed the case.
Also the machine keeps track of how much resin has been dispensed from each cartridge. Manually pouring resin into the tank would not allow proper tracking of the resin.
Edit: You can also safely pause the machine at any time (just give it time to finish the current layer). You can then inspect any problems with the resin/cartridge and then resume printing.