'apropos' crashes GUI on macOS

Help!
1

On Intel macOS 13.5.1, running 9.1.18-70-g955571d43.
apropos in swipl is OK.
If I start SWI-Prolog.app, and run help(help) it freezes. If, instead, I run apropos(help) it crashes.
emacs (for example) works.