When I use the instrument Keyboard instead of Piano (Klavier) then the fingering for intervals and chords get the wrong side. It’s upside down:
No problem with Piano.
No problem with Piano.
Dorico makes certain assumptions for piano, but it doesn’t make those same assumptions for all other instruments, particularly since the fingering features have to work sensibly for other instruments, like mallet percussion (which don’t invert the numbers on the lower of the two staves). However, it clearly should recognise “Keyboard” as being a keyboard instrument, so we’ll fix this in a future version – thanks for reporting it. For now, you could use piano and change its displayed name if this causes you problems.