Whos has Engine ticking on e350 2011? This one is odd??

What is your question?

So I have a 2011 Mercedes Benz E350 4 matic.. when the engine starts everything is fine on the cold start however when the motor warms up to operating temperature there is a slight tick on the passenger side. At about 500 RPM the tick is noticeable but when I apply gas and raise the RPM to 600 Rpm..the ticking goes away and this only happens when the motor is warm can someone please fill me in on whats happening please? Bad lifter? Bad oil pump? I run the recommend mobil 1 synthetic ....is the oil not being circulated at 500 rpm? And thoughts?

What makes this problem better or worse?

It's worse when it is warm

How long has your 2011 Mercedes-Benz E350 had this problem?

Weeks