Why client taking updates from SEPM, even in LU policy SEPM is not selected.

clients are still downloading security contents from Mangement server, while under Policy tab, LU policy, Management server is unchecked.

Client should only get the Policies and assigned task from SEPM and report to SEPM but when cheked in client logs, it is still downloading contents from Management server. 

One more question, if i want my clients should take only policy and task from SEPM, then why "download policy and content from Management server" is given under "Client view----Policy Tab---communication settings".  see attached image, While i dont want that any client should get content from SEPM.