Finder is deleting files AFTER successful transfer OS X -> Win / sharepoint

This is strange but I've encountered it a number of times now. I'll set a bunch of files (large) to transfer as a selected group between my MBP and another windows machine in our workgroup and upon completion, most if not all of the files will be deleted.



Anyway, the behavior is that it will transfer all the files (agonizingly slow on a wireless -> wireless connection) one by one. You can even play them on the receiving end after each one completes.



Then when the transfer finishes, the files will "disappear" from the receiver and can't be recovered. (No recycle bin, just remote delete)



What's even stranger is that the last time this happened, (12 files for ~4gb) it kept the first two files and deleted the rest of the set.



I'm pretty sure that I can reliably reproduce this, it's just painful to do. I've lost all faith in the mac finder though and can no longer straight "move" files from one place to another. I have to copy, verify, and delete. sigh



I'm all patched up with the latest software updates, and I don't think it's the receivers fault because typically that would entail a move the recycle bin (recoverable).



I've experienced this with 10.6.4 as well.



My workaround (which is unacceptable) is to move the files one by one and babysit the entire process.



What's going on here?