Thank you.
That appears to be part of an Amendment made in 2018. I recall when I first received my DE license, and then went to get my PA LTCF, I was cautioned not to carry my sidearm on the way to the Sheriff's office (although it would have been legal to carry back on the way home, provided I was successfully granted my PA LTCF).
I guess laws are constantly changing. It is not always easy to keep up with them.