This sounds like it is
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March 29, 2011 at 9:20 pm #12012
This sounds like it is coming from under the glass. The shelf may not be flat, there may be some small divots. In any case, the air is not able to travel out from under the glass in these areas. If all else fails, put 1/2 mm fibre paper down and then thinfire over it. This ensures the air can get out from under the glass.
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