I have not had this problem. But looking at your photo it looks like the top part of the end of the wireform is bent down too close to the bottom. I'm too lazy to pull the glass off for a better picture - here's one from the top. On mine, the end of the wireform is pretty much the same distance apart as it is from the first brace there. I'd try bending that up and making it more parallel with the lower wire (if that makes sense.)
viperrwk