Obout cron expression question

bug?
1

is use cron job
about “*/15 * * * *” but is don’t excute in 16:15:00 16:30:00 actual 16:15:30 or 16:15:20

2

I can’t share this.
Mind the timezone.

3

i hope the seconds also 00 but not

4

It takes some seconds to enqueue and execurte the job.