Due to a problem in the Quartus® II software, version 14.1 and earlier, even when you enter a non-zero value in GENERATION_ID field in Qsys, Qsys generates a unique value.
To work around this problem, manually edit the .QIP to replace the unique value with the chosen value.
This problem is scheduled to be fixed in a future release of the Quartus II software.
When you set the GENERATION_ID field in Qsys to a non-zero value, Qsys uses that value for the GENERATION_ID rather than generating a unique one.