Is the fuel just dripping out of the vent when the tank is full and the boat has been sitting in the sun? Also, yes, kick back can be made worse if your vent is clogged. That said, I've never had a boat that didn't spit some on me when I filled the tank all the way up and I didn't ease up on the fill rate in time just prior to hitting full. I'm assuming you have had your boat for some time and have filled it many times before? No offense meant. That said, I would verify your vent tube is clear and not kinked. Also, check the fitting on the outside of the hull that the vent tube connects to so as to be sure its clear too. Usually, I think they have a screen material covering the holes so dirt dobbers etc can't get in. I don't think that tank has baffles but if it does I don't know if that would cause issues??? One last thought, is the tank stock or has it been replaced before? If ever replaced, is the vent in the correct place? The vent on a power boat should be in the forward/bow part of the tank. That is probably unlikely but I had a boat where the tank was replaced and the vent was in the rear which caused these type of issues. Now hopefully one of our resident experts will chime in with additional thoughts. Good luck.
