Hello,
I have a JIRA automation setup in my DC instance of JIRA and the automation is pretty straightforward, it runs a JQL every hour, and for any result, it triggers a transition:

The transition has no conditions or validators, it is accessible from all statuses for the issuetype I'm searching for.
The JQL on my testing returned 18 issues, when the automation runs, only 15 issues get transitioned, if I re-run the automation again, the remaining 3 will get picked up and transitioned, I've attached a screenshot below of my automation's log, these runs were triggered back to back manually.

Any guidance on why this could be happening would be greatly appreciated!