If I go to Vault 3 and enter the Recreation Area (first section) then either go to the Maintenance Wing or Living Quaters.....the autosave created from exiting either of those areas back into the Recration Area becomes corrupted by the DLC message. And so are any manual saves made past this point.
Basically I can't proceed past Vault 3s first section otherwise my game is destroyed. I tried it 10 times in a row and it happens every single time.

I experienced the same problem with Vault 34...it's best to avoid the vaults. except for Vault 21, that's fine it's not even technically a vault anymore but a hotel

assuming you still have a save game you can play from right before you went to Vault 3, you should just ignore that part until the patch comes.