Some of our customers are facing issue when all Scheduled Issues are turned inactive.
We have investigated this case with Atlassian (and one of our customers):
The root cause in summary was the exact same time of execution of many issues, it was firing 403 error (licence missing), while it was a timeout issue, but as our app gets response from Jira about missing license, the SI's were deactivated.
As a solution:
Please try to spread creation of sets of your issues by 1 minute eg. in 5-10 minute window.
Additionally:
Please vote for this ticket in Atlassian support system, as it related to issue and will help to fix it:
https://jira.atlassian.com/browse/JRACLOUD-71056
In case ticket don't get much attention, we will try to figure out some other solution, to prevent this situation from happening ( SC-531 )