Java log4j2: Log messages go missing sporadically, especially in multi-threaded scenarios

[hexagon-ecosys]

Expected behavior

All log messages should be sent to App Insights

Actual behavior

Log messages go missing sporadically in multi-threaded scenarios when several threads are logging simultaneously Application Insights log file has no errors

To Reproduce

Clone https://github.com/hexagon-ecosys/azure-app-insights.git and run it several times by supplying the single parameter value '3' (which runs it in multi-threaded mode with long messages upto 20K characters in length)

System information

• App Insights 3.4.18
• MacOS 14.2 and Alpine 3.18 with Eclipse Temurin JDK 21

Additional Information

• I cannot not see any pattern to this issue other than the fact that it happens more during weekdays (we're based in New York City) and less during the weekends
• I am using the preview option generalExportQueueCapacity. Without it, I can see error messages in the Application Insights log file asking that it be set