As Marc said, this is a phrase recognition issue. It depends on what comes before or after the passage in question; Dorico sometimes gets a bit confused and you have to set it straight.
Simply request a change in condensation (in Engrave Mode) and tick the relevant instruments (without making any settings) for the phrase to be recognised and the problem resolved, according to the condensation type you have chosen in the Notation Options.
Below is an example of how to restart a condensation for flutes and clarinets.
Edit: As I like to give credit where credit is due, it was Vadian who explained this to me in a thread from about a month ago.