what causes this bizarre case?

[Ning Zhou]

as usual, we updated arch link, one linked file only, Reconcile Hosting should list only one link, but instead ... (see attached JPG).
what causes Unknown Links appear?

[BenSammis]

My guess is those links are in the ARCH model, and set to "Attachment" rather than "Overlay."

[Ning Zhou]

right, i remembered that one of our Revit users directly updated that arch link w/o clean up a bit, means didn't unload or remove links within that arch model, one of them is using attachment, i fixed that later, but somehow that attachment info is still being reflected as Unknown Links, thanks Ben.