Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 22.2, you may see the intermittent link-up issue after changing the loopback mode on the F-Tile Serial Lite IV Intel® FPGA IP System Console design example when running at 1Gbps datarate.
To work around this problem in the Intel® Quartus® Prime Pro Edition Software version 22.2, generate the F-Tile Serial Lite IV Hardware Test Design Example and insert "after 10000" at line 225 in the ed_hwtest/system_console/sliv_ftile.tcl file.
Example sliv_ftile.tcl after fix on Line 224 to 226:
...
sys_reset
after 10000
}
...
This problem is fixed beginning with the Intel® Quartus® Prime Pro Edition Software version 22.3.