The team has reproduced this and opened bug for fix. Updates will be shared on this post. Sincere apologies for any inconvenience.
Adobe XDMundstrøm commented
Same on Danish keyboard. Mac OS Mojave, Apple Magic Keyboard (bluetooth with numpad) stopped working after May 2019 release.
I know it broke, because the behaviour is hard-wired in my muscle memory and I keep hitting "CMD" and "numpad +" and wondering why nothing happens. Then I think "oh yeah it's broken now"