Operations remain too long active?

[muepet]

I tried the following. I pressed: "5" "x" "4" "=" "3" "+"

After "=" the "20" was displayed. Then, after pressing "+": "60" was displayed. I. e., the multiplication was still "active" after pressing "=", so that "20" was multiplied by "3".

This is not what I have expected. I would have expected that with "3" I started a new calculation. My experience is that "=" usually "ends" a calculation.