Wow, .251 is very old. After the WSUS is on .274, you have restart the whole server. Synchronize with MS and now you can synchronize the downstream WSUS with your upstream. Best way is the Upstream WSUS is the newest available System.
If the WSUS.MSC is installed on a Client/Server with W2008R2 or lower, install on this Clients/Servers the patches too.
If the WSUS.MSC is installed on a Client/Server with W2008R2 or lower, install on this Clients/Servers the patches too.