You are running a DCDiag and its shown a warning by performing the MachineAccount test.
If you are pre-stage a Computer account in ADUC and you promote it later, the userAccountControl is set to 532512 instead of the 532480.
To fix this Bug, open ADSI edit, connect to default naming context and browse to the DC that is affected. Open Properties and go to userAccountControl and click on Edit.
You need to manually set the vaulue to 532480.
After that its set to the standard DC value!