Adding the last line to the /etc/cron.d/passbolt-ce-server seems to calm it down while leaving the source code as-is:
PATH=/bin:/usr/local/bin:/usr/bin
PASSBOLT_BASE_DIR=/usr/share/php/passbolt
PASSBOLT_LOG_DIR=/var/log/passbolt
PHP=/usr/bin/php8.3 <---
As a reference for others, this was based on comments found in the /bin/cake file:
# If your CLI PHP is somewhere that this doesn't find, you can define a PHP environment
# variable with the correct path in it.
if [ -z "$PHP" ]
then
PHP=$(findCliPhp)
fi