Has anyone else seen a problem with dragging (copying) files from a network drive to a DVD drive and the source files being deleted?

Open 2 explorer windows, select files on network drive, drag them to the DVD drive in the 2nd explorer window. It says it cannot find the files and at that point the files have been deleted from the network drive. Tried it on 4 different Win 7 PC's with the same results.

If you copy and paste the files to the DVD drive, it works as expected. It appears to be only if you drag the files to the DVD drive.

IR6 does not appear to have this problem.