I am having issues with some publishers after installing service pack 6.5.7. The author instances appear to be ok. I am seeing this repeatedly in the log .
13.01.2021 03:33:08.391 *INFO* [10.170.16.11  GET /mnt/overlay/granite/ui/content/shell/header/actions/pulse.data.json HTTP/1.1] org.apache.sling.engine.impl.SlingRequestProcessorImpl service: Resource /mnt/overlay/granite/ui/content/shell/header/actions/pulse.data.json not found
I saw a couple of my 6.5.7 publish instances hang up recently, with what Adobe support have attributed to a possible deadock in the service registry. Have a look in your thread dumps and see if you have any blocked threads as per: https://issues.apache.org/jira/browse/FELIX-6252