Slashes not showing in [4+5]/4 meter

I’m writing an arrangement in 9/4. When I create a slash region, there aren’t any slashes in there… When I don’t specify the grouping of the 9 beats though, the slash regions work, but when I use the [4+5]/4 grouping like a need to, the slashes disappear.
Is there something I can do?
Using Dorico 3.1

Dorico is being flummoxed by the fact that a grouping of 5 quarter notes cannot be represented as a single notehead duration; Dorico will not currently notate slashes with ties in slash regions. Could you perhaps use [4+3+2]/4 or similar instead?

Thank you Daniel, I understand. [4+3+2]/4 will work in this case!