Embedding or linking to nodes from XML text fields implicitly creates object level relations to the encapsulating content objects, of type LINK and EMBED, updating ezcontentobject_link table.

When swapping nodes encapsulated content objects of the swapped nodes are exchanged, but ezcontentobject_link table is not updated.

Solution should probably include asynchronous updating of relations.

Steps to reproduce:

1) create content draft of some class containing XML text field
2) in the XML text field create link to the existing node (nb: not content, eg. eznode://12345)
3) publish content
4) swap linked node with some other node
5) clear caches

Now XML field of the created content contains link to the same node id, but that node now encapsulates different content object than before swap.
See ezcontentobject_link table still linking to the content object that node encapsulated before swap.