The atlassian-jira-apdex.log is not being populated since a recent upgrade of Jira Data Center from version 10.3.5 to 10.3.8. (location: Atlassian -> Application Data -> Jira -> log)
Further investigation suggests that the log4j2.xml (location: Atlassian -> Jira -> atlassian-jira -> WEB-INF -> classes) file could require a config update to enable logging but the configuration looks correct.
Has anybody else experienced this issue?