PDM Check Out of Large Assembly

I have a large assembly checked into PDMworks. I've been the only one working on the assembly for a few weeks now. I checked it in before going home last night. Everything was in perfect order. There were no over constraining mates. I wiped everything associated with the assembly out of my folder and checked it back out this morning. Now it lists numerous over defining mates both warnings and errors. I am in full resolve mode, so nothing is coming in lightweight. One of the warnings doesn't make any sense. It says the three mates assembling the first subassembly in is over constraining. The three mates just mate the three datum planes together. This also happened to another engineer that check this out yesterday. I thought it just had something to do with settings on his machine, but now I've repeated it on three different machines.

Thanks,

Eric