Cursor jumping around when typing

Hi, I am using Scrivener 3.1.4 on a Macbook running Mojave (10.14.6).
When editing or typing text in a novel manuscript in document mode, the cursor often jumps midstream and I end up on a different line. Is this a trackpad issue?

I experience the same from time to time, on both a Macbook and a Macbook Pro, but never when I use an external keyboard or when I write on my iMac.