Staccato note triggers A-1

When I change the automatic patch selection for a Trumpet or Trombone player in HalionSE to the alternativ patches “Clear Trumpet NoteExp” and “Shinny Trombone NoteExp”, then a staccato note always triggers a low A-1 note simultaneously with the written note.
Although I can reduce the lower key range to prevent this, it is probably not an intended behavior ?

It absolutely is intended behaviour: Dorico uses Expression Maps to tell it how to map articulations to specific playback instruments
The low A is the key switch that presumably the default patch uses to tap into a staccato articulation, but the patch you’ve switched to doesn’t use the same key switches for articulation.
You can’t just change the patch; you also need to tweak (or create a new) Expression Map to account for the new patch’s articulations.

John Barron did a Discover Dorico session that covered this side of the program, just yesterday:

Thanks, Leo, so I have to dig more into that topic. I didn’t thought about this in the first place because the staccato plays correctly with these patches except for the added low A-1