Why would my final paycheck have an amount withheld as pending?

So I ETS’D November 21,2021, and my final paycheck is a bit of confusing. Anyways, I checked my LES and saw a status det of $2168. Fast forward to December 10th I received a deposit from DFAS for the amount of $1028, which I thought was a little low. i called DFAS and they said there was an amount pending (which I assume is in audit) for $1200, but they have no idea what the $1028 is for. I tried calling my separating base finance but they are completely useless as I called them and no one answered. Any help or clarification would be great.