Hi yuri0001,
In OTRS 3.1.x I don't see that state and article duplicates in Master/Slave tickets.
please install MasterSlave package 1.2.5 since the previous version has some bugs. you also should active all advanced configurations for MasterSlave.
MasterSlave::AdvancedEnabled
MasterSlave::UnsetMasterSlave
MasterSlave::UpdateMasterSlave
MasterSlave::FollowUpdatedMaster
Is this related to Ticket::Acl::Module###1-Ticket::Acl::Module attribute that allows to close parent ticket only after closing child - when it activated?
If "Ticket::Acl::Module###1-Ticket::Acl::Module" was actived, it will make CloseParentAfterClosedChilds and MasterSlave to be conflicted each other, since MasterSlave allow you to close parent(master) ticket before the child(slave) tickets are not closed yet.
I think it is a design flaw. Now MasterSlave relation share the same link type with ParenChild. It will be better to have two different ticket link types, Parent-Child and Master-Slave and apply different ACL for each of them.
micshi