I am writing a xylophone part and Dorico restates the accidentals on every instance in the bar. It doesn’t do this for any other instrument. I tried toggle various Notation options and Engraving options to see if this would change but the xylophone part stayed exactly the same. I’m sure I’m just missing something simple.
Since you are writing simultaneous F and F# in the same chord, I think the cautionary is wise (even on every repetition), which is likely why Dorico adds it.
I would add it manually if the program did not, since it would save rehearsal time confusion.