Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

Platform: debian 11.1 "bullseye", amd64
          Emacs 27.1
          Display on windows 10 using MobaXTerm and SSH tunneling

Arrow up and down scroll the window instead of moving the cursor, when
the buffer has more lines than is visible.

Do anyone know what has caused this and how to make it stop?

I.e. I would like to have arrow up and down move the cursor instead of
scrolling the buffer.

Thanks!