How to stop I-Pencil from drawing on documents with I-pad pro 12.9

I use the I-pencil for navigating all my apps in my I-pad pro 12.9. When I open a PDF attachment in Acrobat, the I-pencil draws lines on the page when I want to scroll.

Yes, I can use my fingers, smearing them all over the screen, but I’d much rather use the I-pencil. I find it much easier to navigate and scroll with it in all my other applications.

Is there any way to turn off this function, as can be done in say, Excell, or Word?

Thanks