Turning off auto-inputting dynamics to multiple staves

How do I do this? Unfortunately, searching isn’t popping up where this is controlled; I just may not be using the correct specific terms, though. Basically, I want to enter in an orchestral score a dynamic for a flute that does not match other instruments and right now the dynamic marking is getting linked to many others.

Right-click on the dynamic and go Dynamics > Unlink.
In Preferences > Note Input and Editing there’s an option at the bottom called “Link dynamics and slurs to existing items when pasting”. You could untick this if you find this functionality unhelpful, but for your current work it’s too late.

Ah, OK.

Unfortunately, I’m not pasting during this operation - just entering a vanilla dynamic.

Sure, but Dorico only links dynamics together in the first place if you’ve copied and pasted those dynamics (or staves, or entered one dynamic and then Alt+clicked it to staves above or below).

I don’t think that’s quite correct. The unwanted dynamics were getting added to staves I didn’t copy notes from. I.e., I copy a measure from violin 1 and paste it into flute 1, then add a dynamic to flute 1 which was automatically added to the F horns (and not violin 1) which had different content (not rests).

If you had linked dynamics in the Flute 1 and F horns earlier or later in the flow (generally within a few bars) it’s conceivable that Dorico would group (horizontally) the existing dynamics and the new dynamic in Flute 1, and thus also link down to the F Horns, but otherwise what you’re describing is inexplicable.