Per this article: https://knowledge.safe.com/articles/87453/getting-started-with-automations.html
Automations display their errors/warnings on the Automations management page under the Status column. The number of errors/warnings displayed is calculated from the total number in the log file. If you want to view current errors you need to view the log file and if you always only want current errors you'd need to remember to clear the log file.
It would be great if there was an option (or change default behaviour) to only have errors/warnings from the latest Automation run displayed in the Manage screen. This would make it much simpler to tell at a glance if the latest Automation run has any issues, rather than having to remember how many errors were reported last time you looked at the page.
If you need to see errors/warnings from previous Automation runs you can always look in the log file...