If there is too large of a disparity between the temperature of the bowl and the applique, then there can be internal stress cracks generated when the decorations are applied or the items cool at different rates. You will see the internal stress fractures around the handles of pitchers with applied handles, generally on the pitcher body as it is produced first and is cooler. This can also occur if the item is not properly annealed in an oven as it is cooled. The annealing, it is my understanding is more critical with thick glass.
A few years ago I picked up a thick bodied contemporary Italian duck at an auction I managed to turn it over and look at the base, and it fractured into many large pieces in my hands as the internal stress from incorrect cooling released. I must have applied just the right pressure in just the right spots. I picked it up with both hands by the sides of the body to roll it over. It did not get bumped or anything when I handled it. The body itself, which was a singular large piece of glass is the part that came apart. It cut me very badly as the pieces of the body were sharper than any razor or knife I had ever handled. Being glass, my first reaction was to try to grab it as I had not realized yet that it was in pieces in my hands. I thought it had simply slipped from an incorrect grip. By the time I realized it had actually come apart I had already been sliced badly. It was quite an amazing lesson about glass. I have never looked at a very large piece of art glass the same since that happened. It made me realize the types of pressures that can be stored in a piece of glass like that.
Craig