I have had this issue on a few different projects so far and it is an absolute nightmare.
(STC = Save to Central)
I will attach a video demonstrating the issue, but in short here it is:
Two users are working in a project that has the need to tag elements in a linked file, they both have the hosting file open. This is a common scenario on our large projects where the drawing sheets are in a separate file to the geometry.
User 1 creates the geometry in the linked file, performs a STC, reloads the link into the sheets file and tags those elements.
User 2 performs a STC on the sheets file WITHOUT reloading links. The tags sync but the geometry isn't there for them to tag, so they lose their host. (??)
User 1 performs a STC on the sheets file and the tags lose their host. (then they come and ask me why)
Tested with Revit 2013 and 2014. Autodesk support has referred me to this page and said to re-host the tags:
Solutions as I see it are for Autodesk to fix it, by adding the option to reload links upon STC. (possibly per file, so you don't need to reload if your not tagging linked elements)
OR, any savvy API guys out there think they could combine Reload all loaded links + STC into one command?
Revit reload links + STC bug.zip
Update: This also happens when elements are mirrored (Since the ID changes)