Custom Chord xml works different in musescore 4

I have a custom chord xml, which is based on the chords_Jazz.xml with added:

7(b9#5)
m:0:&ext; e7 m:0:-&ext; m:0:-2 ( m:2:0 :push sb s9 :pop m:-1:10 s# s5 m:1:-10 ) m:0:2

In MS3, this resulted in a stacked chord if I type c7(b9#5).
In MS4 this doesn't work, but if I type the chord without the (), i.e. C7b9#5 then the chord is shown stacked including the (). When I then edit the chord again, it is changed to C7(b9#5) and even if I don't change anything (just double click and the leave the chord), it is reverted to the default non-stacked notation....

I think there is a bug here.

See attached picture:
Step 1: type chord
Step 2: result
Step 3: edit (double click)
Step4: result (escape)

I am running on Windows 11, using Musescore 4.0.1