Description
Due to a problem in the Intel® Quartus® Prime Standard Edition Software version 22.1 and earlier, you might see this internal error when the CLKOUT port on a PLL_REFCLK_SELECT does not drive a FRACTIONAL_PLL. This can occur if there is a PLL clock output in the design that does not drive any logic.
Resolution
To workaround this problem, either ensure the PLL clock output does drive logic within the device or remove the unused PLL clock output.