Up and down works as expected.
Apple Mighty Mouse 2
CPU-Threads: 8; BS: Mac OS X 10.13.6; UI-Render: Standard; VCL: osx;
Gebietsschema: de-DE (de_DE.UTF-8); UI-Sprache: de-DE
moving finger to left scrolls right
moving finger to left scrolls left
User Profile Reset: No
Naturally scroll-direction is not switched on in preferences.
*** This bug has been marked as a duplicate of bug 126680 ***