Q:

Windows 8.1 locks account after 3 invalid attempts even if GP is not defined

I mistyped my password three times today, and my account became locked on my windows 8.1 pro workstation.   I checked Resultant Set of Policies (rsop.msc) and all three relevant settings are "Not Defined"

Account lockout duration
Account lockout threshold
Reset account lockout counter after

"Account lockout threshold" defaults to "0" and "If you set the value to 0, the account will never be locked out."  
Thanks
Update:
I ran gpresult /h [filename] and no lockout policy is defined at all (confirming all my other comments)

A:

RSOP support has been deprecated.   According to http://deployhappiness.com/gpresult-or-rsop/

"Beginning with Windows Vista SP1, Microsoft made the GPResult command
  the primary tool for troubleshooting Group Policy on a client." 

Basically, to ensure that you are getting the full result of policies on the machine, you need to use GPResult instead of RSOP. 
However, your account is located on the Domain Controller, and therefore, the policy of the Domain applies to lockouts.   No amount of tweaking, configuring, or policy editing will change that on your local workstation.   Any time you enter your password, the Domain must authenticate it, and it will count towards your attempts.   Other things can count against your attempts as well, such as cached credentials, or being logged in to other computers with stale credentials. 
This part is no longer relevant. 

Furthermore, the location of the account is incredibly important!  
  If the account is actually an Active Directory Domain account, your local machine policies will NOT affect your account lockout,
  you will have to check the group policy settings of the domain controller (e.g. run GPResult on the DC).   Accounts stored on the
  domain don't authenticate against your computer, and the lockout is
  triggered on the domain controller, not your local workstation.  
  Accounts stored locally will follow the GPResult, but only after
  you've rebooted the computer since the WinLogon service will have to
  re-initialize with the new GPO settings.   (Not all GPO settings can be
  applied without a reboot).