Wha Sup Wit Dat?

I had a brand new, unused, Yumbrella Rig with five cocahoe swimbaits attached hanging in my garage on a pegboard with some other lures, as well. It had been there about a week and I noticed, today, that the head on the rig had shattered - sorta like hard candy does. I'm thinking, wow, it must have gottn pretty hot in my garage but, then, none of the cocahoes were even slightly melted. So, I'm naturally curious about this.



Anybody have any thoughts, here?



Point of fact: the five leaders were tied together at the bottom with a twist tie, so there would be a little tension in play. I can't imagine that being a factor, tho.