Hi David,

This has nothing to do with User Role Editor.

Scheduled posts are published using WordPress cron. This happened most probably because the cron did not execute on time. It could also happen because of misconfigured caching.

Check whether you have cron disabled. WP cron is invoked from user visits. So if your site do not have frequent visitors, then the cron won’t execute on time. If you are testing this on a development site, this very well could be the case.

There are some plugins out there to fix this issue. I never used it and I don’t know how effective they are.

Check out this link https://wordpress.org/tags/missed-schedule

Thanks

Syam