Critical Issue
Due to a problem with the Intel® FPGA Triple-Speed Ethernet IP designs targeting the Intel® Arria® 10 and Intel® Cyclone® 10 GX devices may fail simulation when using the Mentor* Modelsim simulator in the Intel® Quartus® Prime Pro software version 19.1.
To work around this problem, turn off optimization in the simulator by replace the "-voptargs= acc" flag in simulation script msim_setup.tcl with "-novopt" flag.
This issue has been fixed starting in version 20.3 of the Intel® Quartus® Prime Pro software.