Surfing Waves

I got an M5 fcs fin set today and the left fin is loose in the like upper most hole. I screwed it in but theres about a cm of space in there. Is this alright, will it fall out or anything? Can I add some resin and sand it to thicken it up and fit in the hole?

Try a little duct tape in the front tab where the gap is. Resin and sanding works too.