led_link port of 1G/2.5G/5G/10G Multi-rate Ethernet PHY (alt_mge_phy) keeps toggling

When the optical cable is not connected, the led_link port of the 1G/2.5G/5G/10G Multi-rate Ethernet PHY (alt_mge_phy) macro keeps toggling.

Also, we observed strange packets (with unknown ethernet type) coming out of its rx interface.

When it is in reset, or the cable is connected, the led_link port is not toggling and no strange packets come from the rx interface.