ram retiming

In my project with agilex7, I have added the following the setting:

set_global_assignment -name ALLOW_RAM_RETIMING ON

so I think quartus tool should execute the ram retiming

But the fit.retimg.rpt still report the following retiming restriction:

; Retiming Restrictions at Register #1: ; x_blk_fb|x_tdb|x_tdb_rctrl|x_tdb_rctrl_mporead|x_tdb_rctrl_mporead_pld|x_mpo_pld_fifo|x_scfifo|auto_generated|dpfifo|FIFOram|altera_syncram_impl1|ram_block2a1025 ;

; Node is in a RAM or DSP block that cannot be retimed. ;

; Manually adjust your RTL design to add additional registers or re-position registers along the path to balance slack ;

so how to fix the ram retiming restriction?