Description
Due to a problem with the Intel® FFT IP core in Intel® Quartus® Prime Standard software version 18.1, you may observe that the last output frame of the FFT IP core is missing EOP when both the Input Order and Output Order are configured to Natural and there are intervals with sink_valid = 0 between input frames.
Resolution
Configure the Output Order in FFT IP to be Digit Reverse.
This problem will be fixed in a future version of the Intel Quartus Prime Standard software.