Re: Cron sometimes starts two jobs from the same crontab entry

[Cameron Simpson]

On 08Apr2020 14:54, Terry Barnaby  wrote:
> Note this has happened a few times this year, (approx 1 in 64 x) so not 
> related to DST changes anyway. Might be due to chrony clock resyncs I 
> suppose but I think something stranger is going on here or something 
> silly and obvious in what I am doing.
>
> I will have a more detailed look at the system and my backup shell 
> script and create a simple test cron job to see if it shows the same 
> thing ...

How about sticking:

echo "`date` [`date -u`]: start $0 $*" >>some_log_file

at the start. Makes sure the job is actually starting at the cron time.  
Might tell you more about the system time situation.

Cheers,
Cameron Simpson