Odd results while enameling or enameling prep

I’m having two odd situations happening at the same time in my

I haven’t had this situation happen before.

I’m putting Rio Scalex on one side of a copper sheet and Thompson’s
Counter Enamel #3 (a nice bluish color) on the other side.

When I fire the piece, two odd things happen:

  1. When I remove the scalex, most of the time the sheet of copper on
    that side is no longer smooth. It’s almost as if there has been some
    light acid etching. In addition, when this phenomenon occurs, the
    copper looks like a very bright shiny brass instead of copper. Not
    all pieces get this, but for the last two firing sessions, most of
    them are.

  2. The counter enamel is pinging off in a series of small circles a
    pencil lead in diameter, about 1/4 to 3/8 inch apart.

I’m firing at 1500F. I started using the kiln last fall and did not
have this problem.

I haven’t varied the cleaning prep routine.

Using the standard Rio pickle.

Any ideas?