Log says files have been moved, but still in source?

I have some very simple rules that find files based on the name and move them. The log shows that the files are being moved, and they are. The problem is that the originals are not being removed.

If it matters, the source and destination are both dropbox folders.

Screenshot showing supposedly successful move and that file is still in the original folder: https://db.tt/Vxin3r5A

Is the file still being written to by some other program? If so, Hazel could be moving it and then the file gets re-created. In such a case, you might want to add a condition like "Date last modified is not in the last X minutes" to delay Hazel from processing the file.