Debian’s vixie-cron had a bug [0] where if the system TZ was changed without restarting crond, it would continue to run jobs based on the old TZ. It checked for DST transitions, but not TZ.
In fairness, it’s not something that should happen much at all, if ever.
[0]: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1019716