I am trying to filter multiple values from two fields but not getting the expected result.
index=test_01 EventCode=4670 NOT (Field 1 = value1 OR Field 1 = value2) NOT (Process_Name = value 3 OR Process_Name = value 4)
I am geting splunk results which includes Process_Name=value 3 and Process_Name=value 4
Are you sure your value 3 and value 4 do not contain, for example, white space? I cannot help but notice that you did not quote "value 3" and "value 4". If the search is illustrative, it should be something like
index=test_01 EventCode=4670 NOT ("Field 1" = value1 OR "Field 1" = value2) NOT (Process_Name = "value 3" OR Process_Name = "value 4")
Your search looks OK - can you share some of the events (anonymised of course) which are being found which shouldn't be?