Why does the HDMI Intel® FPGA Sink IP encounter intermittent HDMI 2.1 Rx link training failure ?

Due to a problem starting in version 19.4 of the Intel® Quartus® Prime Pro software when using Intel® Arria® 10 Devices, and version 20.4 of the Intel® Quartus® Prime Pro software when using Intel® Stratix® 10 devices the HDMI Intel® FPGA Sink IP may intermittently encounter HDMI 2.1 Rx link training failure.

This problem is due to the HDMI Intel® FPGA Sink IP core does not perform symbol re-alignment correctly if the FRL lock signal becomes unstable after initial locked stage.

This problem is fixed starting from the Intel® Quartus® Prime Pro Edition version 21.1 software.