OK, heat it is. No question 118 is HOT. Of course, as has been mentioned, dark glass/carbon will absorb heat from sunlight, but most any dark material will - including veneers. I would expect the glass to further insulate the bow core retaning the increased temperature internally. 118 in the open air may have resulted in a significantly higher temp at the limb core. I guess we all can learn from this one!
Possum Head, south MS is hot! But it's the humidity that get's you! (how many times have your heard that before :D )