My link was to a commercial site and had to be deleted.
Now trying to explain again with this image.
No matter if cabochon stone or enamelled plaque, there is bezel setting (1).
The rim of the bezel is pushed inwards to fix cabochon or plaque (2).
So, there is not even a fraction of millimeter gap between bezel rim and cabochon or plaque.
If your plaque was not set this way, damaged plaque may have been replaced with another plaque.