Mismatch between expected output and actual output when running testbench

[xldeng-chn]

Hi there, I was running the testbench for the design of 65536-point FFT with 256 streaming width. In terms of fixed-point representation, I set 8-bit integer and 8-bit fraction. Under this setting, I encountered the case that the actual output is mismatched with the expected output. I have seen the output of some points are really close to the expected output, while some have a large gap. I would like to know if this case is normal and if this is due to the precision loss of fixed-point representation. Below, I capture part of the testbench output. I would really appreciate a quick response.