My gut reaction is that there is no fix to this.  But we had a person who went and changed the subjects of all the transmittals/submittals in a job so they were shorter and more concise.  Then a client said they were getting the error that the files were not available anymore when attempting to download. 

ERROR: The requested item was not found. It may have been deleted by a Newforma Project Center user. Contact the project team member for more information.

I assume this breaks the links to the associated files for download?  Is there a fix?

I had her re-send the info via info exchange and this works as a work around.