See also org.jboss.weld.context.AbstractConversationContext.deactivate(). A user may send multiple parallel requests. In this case the cleanup may result in ConcurrentModificationException or some other inconsistencies.
There is a fix in eap6.2.x branch: https://github.com/weld/core/commit/025ebff5dd3bda33a5b3c83eeaddb1c90403106f
Marek Schmidt <maschmid> updated the status of jira WELD-1623 to Reopened
Martin Kouba <mkouba> updated the status of jira WELD-1623 to Resolved