Stems in upward-facing slash voices behave strange

For the left hand of a Styrian Accordion I’m writing the bass notes in an downward-facing voice while I write the chords as upward-facing slash voice.

Although there are no other upward-facing voices in the way, the stems of the slash voice behave really strange - facing up and down with no real logic it seems.

Could you attach a short excerpt of the project itself that we could take a look at?

Here’s the beginning of the piece. In the meantime I forced all the stems of the slash voice to face upwards and everything else down.

For this file I removed the forced stem direction to default.
Frühlingsstimmen.dorico (937.6 KB)