Frame_locked stays asserted after unplugging the cable link when receiving data in standard definition (SD) mode. The locked signal indicates the wrong status.
The problem is caused by the serial digital interface (SDI) core being stuck in the previous state after receiving invalid data from the transceiver when the cable is unplugged.
This issue affects version 12.1.
There is no workaround for this issue. Press the reset button or re-plug the cable to restart the receiving process.
This issue will be fixed in 12.1sp1.