Cite group document in word (by using mendeley plugin)

Hello there, within our study we are using a Mendeley group to share documents in our Team. Recently I wanted to cite a document which is shared in our group within a Word document by using the Mendeley Word Plugin. Unfortunately, Mendeley couldn't find the document as long as it has been listed in the group. As soon as I moved the document from the group to my local library I was able to cite it. I'm not sure if this habit is caused by the usage of a "free" Mendeley group (our group is private but it also didn't work by using an "open" group) or if it is a bug? Many thanks in advance!