I wanted to post this and see if others have seen this issue.
If you use Move-PWDocumentsToFolder, with the -CreateVersions switch enabled, does it fail for you too? The command fails if the folder that I am moving to documents too doesn't actually contain a document.
Hope this makes sense,
I tested this in 184.108.40.206 and did not have the issue. Files moved correctly. It does fail (as expected) if the datasource option "Documents having versions can be moved" is unchecked.