Emacs starts up without window focus in macOS Sonoma

I've been using Emacs For Mac OS X on macOS for quite a few years, and it's been working really well until I upgraded to macOS Sonoma (v14.1.1). When starting Emacs now from the command line (from the dock is still OK) the Emacs window starts without focus. I'm on Emacs v28.2. How can I solve this problem?