It was noticed last week that a Missing Timestamp attribute was causing ConfigMgr 2012 Sp1 Client installation issues. Specifically when trying to do client push or via an OSD Task Sequence the client would try and install MicrosoftPolicyPlatformSetup.msi and would error out with Return Code 0x800b0101. Obviously this needed to be resolved and a hotfix was released shortly after. Below is the KB article with a hotfix which will need to be applied to all site servers in your hierarchy, once applied Client Push and OSD will continue to work and problem solved. Hope this helps anyone running into this issue.