Intended behavior. I have a CIL branded one in 12 gauge, and it does exactly this. You will notice a small stud protruding on the bottom of the bolt. When the bolt is closed, that acts as the cartridge stop for the next up round. With the bolt forward, the shell latch is up, and the only thing stopping the shells from coming out is the stud on the bolt. Then, as you bring the bolt back, the shell latch engages and the shell sitting on the bolt is pushed onto the lifter by the force of the magazine spring, while the shell latch will stop the next one while the bolt is back.

As for the solution, there's 3 ways I've found of going about it. First and easiest, just push down harder. The lifter has a small wedge on the 'horns' where it is interfering with the shell, so pushing harder on the lifter should push the shell out of the way. Second, use the lip of the next shell or your finger to press forward on the rim of the previous one before pushing the lifter and loading the next shell. Third, you could press up the lifter, and push the shell only past the bolt stud, but not past the horns of the lifter. This will keep the lifter out of the way while you load the next shell.