You might notice that your Channels are not updating on Sundays. However, on Monday, they are updated as expected and you wonder why that happens.
This issue is due to the fact that every Sunday, the FirstRain document flow is paused due to the Maintenance window. A full reindexing (single segment index re-optimization) happens at the Document Solr Core. While this process is running, the DocFlow is halted. This process can take from 12 hours up to 16 hours. After the maintenance finishes, the backlog of documents gets processed and indexed, so there's no content loss, just an indexing delay and the channels would be updated by Monday.
If you have further inquiries please create a support ticket.