Symantec Management Agent Plug-ins do not upgrade or download the wrong MSI. Upgrade policy doesn't run even when enabled.
Inventory Plug-in policies are sending down the x86 version to all Windows x64 systems
Previously the policies were cloned. Cloned policies are not upgraded when the Solution is.
Delete the cloned policy and either use the default policies, or clone the new version of the install or upgrade policy (right-click > Clone). If you use cloned policies, remember to delete old policies and reclone when a new version of the plug-in policy is released / upgraded.