Dorico 5 stem direction

Hi there, I’m trying to make a lead sheet in which there are indication for drum hits etc. When I try to change the direction of a single note stem in a bar, ALL the notes of this bar (+ the 8 bars before it) change their stem directions… how is that possible? It does it by using ‘F’ as well as ‘force stem up/down’… Does anyone have an idea why? Thanks in advance.

It sounds like you’re changing the overall voice direction, rather than just flipping the selected stem. Can you attach the project itself here?