I'm having this issue (cursor jumping to the top of the note during typing) on the web version 10.6.9-web, Windows 10 using Microsoft Edge. Does not happen to me using any other application or web form on this laptop.
I do have a rather long note and it appears to happen when the cursor is at the bottom of the window. As I am typing the cursor is suddenly at the top of the window and I have to remove all that I've typed from the top and replace my cursor where I want the text to be (I'm not always looking at what is being typed on my screen, rather I am looking down at a document I am transcribing, etc.). I try to scroll the window up so that my cursor is at the top or middle as I type but forget to keep doing that as I go.
Hope this can be fixed. Thank you.
p.s. as I returned to Evernote after typing this entry, I realized another horrible side effect. It appears that every time the cursor has jumped to the top it has created a duplicate note. The duplicated note ends where I was typing and has the mistaken typing at the top of it. I ended up with 4 of these duplicate notes now. Hope this can also be fixed. (see the attached screenshot)
p.p.s. as I continue to use Evernote for my research, I realize that the problem is happening when I have the cursor set to the middle of the page. I don't think the cursor at the bottom of the page is the problem. It seems to be happening as I am typing away, and then if I pause my typing. It does not happen right away. If it starts to happen then it happens very frequently until I click onto a different note and then return to the note I am editing. Then the problem does not happen for a while. Hope this helps.