Double Drum Duration

What’s going on here? I want the 32nds to be doubled to 16ths,
Works fine if all the same instrument… but not so much if various instruments within a kit:

Is there a way to accomplish this within Dorico?

It’s a bit of a pain, but if you go to Layout Options and temporarily make the percussion kit appear as a set of individual instruments rather than as a single five-line staff, it’ll work as you expect. (Make sure you have Insert mode active.)