Ruler Not working on PDFs

I have noticed that the ruler does not play nice sometimes and simply does not work. I have figured out that if you rotate the file in PDF app, the ruler stops working. Go back to original rotation and it works, therefore it is glitch in the app.

I answered my own question as the previous answer was typical I.T. answer "Turn it of and on" which did not work.

Hopefully this will help and someone in Apple will eventually fix the glitch. Also what would be cool would be a way to calibrate the ruler to the pdf (zoom in and out), lock the pinch to zoom, so as to draw accurate markups on the PDFs.