screenshot, in the players list, the horns are listed as Horn 1 in F, Horn 2 in F, etc. But in the score, at the right, the names come out as F Horn 1 1, Horn 2 2, etc. I’ve tried removing the numbers in the players list, but it makes no difference.
You have to change the Instrument name, not the Player name. Open up the player (on that little downward pointing arrow next to its name, on the right) and open the contextual menu for the instrument name.