Q: Media disconnected in FCP7, corrupt Xsan?

Hi folks, I posted this in the FCP7 community as well, but am unsure if it's an FCP or an Xsan issue...

I ran across this issue a month or two ago with one of my student workers.  We were able to fix the problem on the fly and I just assumed it was user error that caused his files to go wonky, but now I can't see that as the answer.  I don't really know how to describe the problem without just saying what exactly happened:

I exported a video yesterday morning.  The sequence was perfectly intact and there was no missing media anywhere in the project (which isn't big, 1 sequence, and only about 15 gb of ProRess422 movies in 18 clips).  After exporting I closed the project; throughout the rest of the day yesterday I worked on other projects, but never that project.

Today, I opened the project and 6 of the 18 clips show up as offline.  When I click reconnect, FCP tells me it's looking in the root directory of the Xsan for the clips, where they have never been located.  I did a Log and Transfer from a Canon Vixia first thing when I started the project so the .mov's went straight to the Capture Scratch (which has never moved). 

When I go to "Locate" the files, the clips in the Capture Scratch that I should be able to reconnect with are grayed out.  If I deselect "Matched Name and Reel Only" then I can select the file I want, but when I do I get the message: "File Attribute Mismatch - some attributes do not match the original, etc.."  If I say "Continue" then it reconnects and ends up being the wrong file (that threw me for a loop).

So after this happened I went into my Finder into the Capture Scratch and went through the 18 clips.  It looks like what happened is some files were deleted, and then replaced with the same name but with a different file.  Specifically: I have clips 138-155.  Clip 146 is now the exact same as Clip 153, whereas yesterday morning they were completely different.

Has this happened to anyone else?  It could very well be an issue with our Xsa, but I've only noticed the problem in FCP.

Running FCP 7.0.3, and OSX 10.6.8 on MacPro and Xsan.  Xsan is hooked up via fiber.

Thanks!