Lsass.exe permissions issue

Question

lsass.exe will generate numerous Audit Failures, in groups of three or more, because it is requesting SeTcbPrivileges but, other times, it will be granted the requested privilege. I would like to know why it is generating all these failures
but, ultimately, I just want to make them stop filling up my Security Log. As it stands, the System, Administrators and users all have "Read & Execute" permissions. Only the "TrustedInstaller" has full permissions. OS is 2008 r2, x64
w/SP1.
Also, this is happening across all servers in the domain and it started long before I inherited the system so i can't trace it back to some patch or change in roll/feature.
Thanks in advance.

Answer 1

And, here is a successful event that happened a few seconds later. I realize that it is being called by a different service but i don't understand why the privilege levels are different.
Log Name:      Security
Source:        Microsoft-Windows-Security-Auditing
Date:          9/5/2013 10:58:51 PM
Event ID:      4673
Task Category: Sensitive Privilege Use
Level:         Information
Keywords:      Audit Success
User:          N/A
Computer:      [FQDN]
Description:
A privileged service was called.
Subject:
 Security ID:  SYSTEM
 Account Name:  [Server$]
 Account Domain:  [Domain]
 Logon ID:  0x3e7
Service:
 Server: NT Local Security Authority / Authentication Service
 Service Name: LsaRegisterLogonProcess()
Process:
 Process ID: 0x204
 Process Name: C:\Windows\System32\lsass.exe
Service Request Information:
 Privileges:  SeTcbPrivilege
Event Xml:
<Event xmlns= [unallowed Microsoft link]>
  <System>
    <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-A5BA-3E3B0328C30D}" />
    <EventID>4673</EventID>
    <Version>0</Version>
    <Level>0</Level>
    <Task>13056</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8020000000000000</Keywords>
    <TimeCreated SystemTime="2013-09-06T03:58:51.939035500Z" />
    <EventRecordID>4292000</EventRecordID>
    <Correlation />
    <Execution ProcessID="516" ThreadID="532" />
    <Channel>Security</Channel>
    <Computer>[FQDN]</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="SubjectUserSid">S-1-5-18</Data>
    <Data Name="SubjectUserName">[Server$]</Data>
    <Data Name="SubjectDomainName">[Domain]</Data>
    <Data Name="SubjectLogonId">0x3e7</Data>
    <Data Name="ObjectServer">NT Local Security Authority / Authentication Service</Data>
    <Data Name="Service">LsaRegisterLogonProcess()</Data>
    <Data Name="PrivilegeList">SeTcbPrivilege</Data>
    <Data Name="ProcessId">0x204</Data>
    <Data Name="ProcessName">C:\Windows\System32\lsass.exe</Data>
  </EventData>
</Event>