Description
Due to a bug in the Quartus® II software version 13.1 and earlier, you might see temperature-dependent CDR loss of lock on Cyclone® V GT device receiver channels.
When the device junction temperature is approximately 75 degrees C or higher, CDR loss of lock may be seen due to an incorrect CDR setting when the transceiver is configured as the data rate of 6.144 Gbps.
Resolution
This problem is fixed in Quartus® II software version 14.1.