warn against consecutive super

Author: mensfeld

Monitoring-and-Logging.md

@@ -542,6 +542,10 @@ end
 
 Such a custom monitor will intercept specific events while delegating to the parent monitor to maintain framework functionality. This pattern enables proper error handling, cleanup, and integration with external monitoring systems that require execution to be wrapped in a block.
 
+!!! Warning "Avoid Calling super Multiple Times in Custom Monitors"
+
+    When overriding Karafka’s instrumentation monitor (`Karafka::Instrumentation::Monitor`), it's crucial **not** to invoke `super` more than once within the `instrument` method. Calling `super` multiple times will cause the original wrapped block of code to execute repeatedly. This can lead to severe and unintended side-effects, such as duplicated message processing, incorrect consumption behaviors, and unexpected logic execution. Always ensure your custom monitor calls `super` exactly once per event, guarding against unintended duplicate invocations.
+
 ## Implications of Broken Instrumentation listeners/listeners Causing Errors
 
 Instrumentation and monitoring listeners are essential components in Karafka-based applications as they provide insight into the app's performance and behavior. They are critical in collecting metrics, measuring response times, and tracking other performance data. When functioning correctly, they enable efficient identification of issues and performance optimization. However, their malfunctioning could lead to several challenges and problems.