Why does the F-Tile PMA/FEC Direct PHY FPGA IP fail to function correctly when the “FGT PMA configuration rules” parameter is set to “GPON”, the “PMA data rate” parameter set to “248832 Mbps” and the RX Auto Adaption is set to “Bypass”?

Due to a problem in the Quartus® Prime Pro Edition Software version 23.4 and newer, the F-Tile PMA/FEC Direct PHY FPGA IP will fail to function correctly when the FGT PMA configuration rules parameter is set to "GPON", the PMA data rate parameter set to "248832 Mbps" and the RX Auto Adaption is set to “Bypass”.

This configuration is commonly used in 25G GPON designs, and typical failure modes that will be exhibited are RX bit errors or link failure and unrecoverable.

There is no workaround for this problem.

This problem has been fixed in version 24.2 of the Quartus® Prime Pro Edition Software.