CI: failures of wkld-cronjob-testing job

in many runs ofwkld-cronjob-testing jobs, such as https://gitlab.com/sylva-projects/sylva-core/-/jobs/8593057748#L91:

$ .gitlab/ci/scripts/cronjob-test.sh
Fetching all cronjobs from all namespaces...
Creating job -test-e04e3526 from cronjob  in namespace ...
error: unknown shorthand flag: 't' in -test-e04e3526
See 'kubectl create job --help' for usage.
KO: Failed to create job for cronjob  in namespace 
All jobs processed. Report generated at /builds/sylva-projects/sylva-core/cronjob_report.txt.
CronJob Test Report - Tue Dec 10 00:08:09 UTC 2024
------------------------------------
KO: Failed to create job for cronjob  in namespace 
KO: Failed to create job for cronjob  in namespace 
Some jobs failed

/cc @loic.nicolle