Why is the PRESERVE_UNUSED_XCVR_CHANNEL .qsf assignment generating an error in the Fitter stage of compilation?

Description

Due to a problem in the Quartus® Prime Pro Edition Software version 25.1 and earlier,  you might see the following error when including the PRESERVE_UNUSED_XCVR_CHANNEL .qsf assignment for Agilex™ 5 FPGA devices with a single GTS transceiver bank: 

Error(24540): You have powered down all transceiver banks through the QSF assignment(s) 'set_instance_assignment -name PRESERVE_UNUSED_XCVR_CHANNEL OFF -to <pin_name>'. Thus, no transceiver channel is available. Modify the QSF assignments to power on at least one HSSI quad. 
 

Resolution

This problem is scheduled to be fixed in a future release of the Quartus® Prime Pro Edition Software.