Description
When you assert local_self_rfsh_req on DDR3 SDRAM UniPHY based memory controller, you will notice mem_cke does not deassert, but it is pulsing like a clock signal.
Resolution
You will have to make a change in {instance_name}_controller_phy.sv file generated by the IP.
Scroll to line 448 and change
.MEM_IF_CKE_WIDTH ( MEM_IF_CKE_WIDTH ),
To
.MEM_IF_CKE_WIDTH ( MEM_IF_CLK_EN_WIDTH ),
This issue will be fixed in a future version of the Quartus® II software.