Different fields look alike if they have the same /AP/N before value change

See attached SO answer - in the attached file, different fields point to the same /AP/N object. I think this could be fixed by changing AppearanceGeneratorHelper.setAppearanceValue() by removing the "if" segment in if (appearance != null && appearance.isStream()) and keep the "else" part only.

I'm wondering why we are reusing the existing appearance stream, is there are use case to this? I ran the tests after making the change and there was a difference but it was invisible.