iPad annotations being 'corrected' after input

I recently bought an Apple Pencil for my iPad in the hope that I could mark up PDFs using Acrobat. At first I was very impressed with the functionality (using the Comment and then little pencil tool to activate mark up), but then I came across a problem with which I hope someone is able to help.

I often work on large pages (up to A3) on which the element I am marking up is small, eg 9 point text. When I zoom in to mark it up everything works well at first, but then I tap the pencil icon again and Acrobat modifies my marking usually changing it beyond recognition. My guess is that this is an automatic 'correction' to fix any deviance from a smooth line during my input, and it's reading my small annotation as something that needs smoothing out. I've attached 'before leaving annotation' and 'after leaving annotation' screenshots to illustrate the problem. The text 'Bassoon' is 9 point, just to give you a sense of scale.

Is it possible to turn this correction feature (or whatever it is) off entirely? I've searched the internet to no avail.

Thanks in advance,

Ed