Event Handler triggering twice generally happens with multiple events trigger when a page is activated (like one ReplicationAction event and/or ResourceEvent for any change in resources etc.) To handle this - write a condition to handle your ReplicationAction event only @Slf4j@component( service = E...

Generally Adobe - AMS provide New Relic monitoring - please check with your AMS or Adobe Support.   NewRelic Dynatrace JMeter (open source)   above are few different tools available, New Relic: New Relic is a powerful application performance monitoring tool that can provide insights into your AEM se...

Please go through WKND tutorial for SPA (vue or react etc)   https://experienceleague.adobe.com/docs/experience-manager-learn/getting-started-with-aem-headless/overview.html?lang=en     https://www.mavice.com/blog/integrate-a-spa/   For CORS issue - please check below CORS: AEM by default doesn't al...

Are there any dependencies between Custom Bundles and Core AEM bundles - check your pom.xml file dependencies

In AEM - General rule or scenario: When you unpublish a parent page, it attempts to unpublish all of its child pages as well.   In the above your scenario - as the child page is deleted (without unpublished) - it will be remain available in Publish instance (remain published) , even after the parent...

It is not a best practice nor recommend way to call a servlet from scheduler. You can call a service from scheduler. Move the existing logic in Servlet to a OSGi service or write a new service and call that OSGi service in your scheduler.This promotes better separation of concerns, code reusability,...

can you try with lower version of PDF services SDK - which is compatible with slf4j version   like pdfservices-sdk-3.5.1.jar is good with slf4j 1.7.26

How did you set the OSGi configurations and run modes?

Consider checking logs and thread dumps for any long waiting threads - connection pooling. Are you using any tool to monitor your connection pool usage. This can help you see how many connections are being used at peak times and whether your application is frequently waiting for a connection to bec...

Did you check the error logs for more details?