Alerts not sent between 15:00–09:00 UTC

I’m using Metabase Cloud Free (v0.56.8) with timezone set to UTC. I have several alerts configured to run hourly and send results to Slack. Since 2nd October, some of these alerts consistently stop firing every day at 15:00 UTC and only start working again at 09:00 UTC the next morning.

Could you share a link to your Metabase instance and the specific alerts that are not working?