m_AliasedBy could contain the same alias more times, breaking internal invariant that it is set.
alias method was tweaked to unalias previous alias. The method is used a lot together with creteProperty. As createProperty does nothing if the node already exists, alias does also nothing if it gets aliased to the same node.
https://trello.com/c/SHVfnz7s/167-bug-error-500-on-removedevice