Cron jobs are not started

On one of my projects, the nightly cron job has not started at all since it has been created, on another - it stopped being invoked after I pushed some changes to the branch. Is this a common problem?

Could anyone please respond something? From the documentation nothing specific about the set up for running cron is written.

Can any of maintainers or contributors can’t simply answer something? Like “provide more information please”, “we already know the problem”, anything?

Found this in logs:

{"commit":"c608fa3da38b83201a1060cffa97f87890afa6db","event":"cron","level":"info","msg":"trigger: skipping pipeline, does not match event","pipeline":"release","ref":"refs/heads/master","repo":"group/repo","time":"2019-10-06T00:03:46Z"}

I think, the cron event must be specified in the list of events explicitly.