52 minutes ago, Anna N said:Are you suspecting the microwave? I'm sure it's possible. I have just never had it happen to me in many many years of using a microwave.
No. I didn't think that.
It probably happened elsewhere and I just didn't notice. In fact, I didn't notice it when washing the plate; just in the photograph.
No great worries. I like that plate but I have several and the place I bought them still has more.