Do compact fluorescent bulbs have problems close to metal?

I love CFB's and use them in many positions (pointing up, down, and sideways) and have had no problems. But when one went out over my sink, I found damage to the base where the gl tube enters and similar but less damage to the other one in the fixture. This fixture is an enclosed cylinder gl about a foot across that is rated for two 60 watt incandescents so heat should be much lower with CFB. The inside surface above the bulbs is covered with about a half inch of fibergl insulation with aluminum foil on that. The gl of either kind of bulb touches the foil but the base of a CFB is only near it. The bulb was screwed in so one of the gl tube entry points was about 1/8" away from the foil. The plastic was brown in color and cracked as shown here a href="http://www.flickr.com/photos/9672970@N08/4300393611/" rel="nofollow"http://www.flickr.com/photos/9672970@N08…/a does having the aluminum foil that close result in high voltage discharge to do the damage or what other suggestions do you have?