Due to a problem in the Intel® Quartus® Prime Pro Edition Software version 22.4, you might see the problem that the MAC transmit Datapath of Triple-Speed Ethernet Intel® FPGA IP fails to work SGMII link at 10M/100M speed when configured for 8-bit FIFO.
A patch is available to fix this problem for the Intel® Quartus® Prime Pro Edition Software version 22.4.
Download and install patch 0.13 from the appropriate link below, then re-generate your programming file.
This problem is fixed beginning with the Intel® Quartus® Prime Pro Edition Software version 23.1.