Hello all! I am a potter of several years but know that I still have a lifetime of learning to do. I have a very particular aesthetic I try to accomplish with my mugs-- essentially they are liner glazed interior with a thick coating of multiple glazes on the exterior. Many potters do this, amiright? I have been creating these intricate glazes myself for 3 years now, without issue. It seems like all of a sudden (last 4 months) I have had customers come to me saying that their piece has been fine during multiple uses, when all of a sudden they pour their hot liquid in, get a ping, and a horizont