Intel Floating Point FFT IP Gives Different Result to Python Example

I have experimented more with this issue and found the intel design example located here:

https://www.intel.com/content/www/us/en/design-example/714680/cyclone-10-gx-fft-to-ifft-with-natural-input-and-output-order-using-cosine-data-example-design-17-1.html?wapkw=fft%20ifft

I extracted the project archive, compiled it, generated the simulation IP setup scripts (Tools > Generate Simulator Setup Script for IP) and top level verilog representation of the block diagram design file (EDA Netlist Writer).

I then ran this through the simulation and achieved the following result:

The description of the example project claims that "When both the FFT and iFFT are operating as expected, Cosine data will be recovered and observed at the iFFT output."
The output seen in the simulator is not the cosine wave as expected.

I have attempted this in both:
Quartus 17.1 Prime Pro* + ModelSim - Intel FPGA Starter Edition 10.5c

Quartus 21.4 Prime Pro+ QuestaSim - Intel FPGA Edition 2021.3

Both attempts yield an unexpected output - source_real and source_imag are not cosine waves.

(below is the output from the QuestaSim simulation)

*Questa 17.1 Prime Pro fails a full compile - the log can be seen below. I have checked and the file it claims to be unable to load does exist in the directory listed.

Problem Details
Error:
Internal Error: Sub-system: DCALC, File: /quartus/ddb/dcalc/dcalc_bcm_modules_cache.cpp, Line: 116
Could not load pdb file - c:/intelfpga_pro/17.1/quartus/common/devinfo/cyclone10gx/ddb_cyclone10gx_io_48_3v_tile-ff-3-0-hs_model_debug
Stack Trace:
    0x5d410: DCALC_TIMING_MODULES_CACHE::get_model + 0x21dbc (ddb_dcalc)
    0x2f2cb: DCALC_TIMING_NETLIST_MANAGER_IMPL::load_model + 0x43 (ddb_dcalc)
    0x41631: <lambda_27927aa62a013f38f2f5db62a47234ba>::operator() + 0x71 (ddb_dcalc)
    0x41446: tbb::interface6::internal::partition_type_base<tbb::interface6::internal::auto_partition_type>::execute<tbb::interface6::internal::start_for<tbb::blocked_range<int>,tbb::internal::parallel_for_body<<lambda_27927aa62a013f38f2f5db62a47234ba>,int>,tbb::auto_partitioner const >,tbb::blocked_range<int> > + 0x6e (ddb_dcalc)
    0x413d0: tbb::interface6::internal::start_for<tbb::blocked_range<int>,tbb::internal::parallel_for_body<<lambda_27927aa62a013f38f2f5db62a47234ba>,int>,tbb::auto_partitioner const >::execute + 0x20 (ddb_dcalc)
    0x1c1f3: tbb::internal::custom_scheduler<tbb::internal::IntelSchedulerTraits>::local_wait_for_all + 0x193 (tbb) at d:\sj\nightly\17.1\240\w64\acds\quartus\extlibs64\tbb\tbb42_20131118oss_altera\src\tbb\custom_scheduler.h:472
    0x19afe: tbb::internal::arena::process + 0x18e (tbb) at d:\sj\nightly\17.1\240\w64\acds\quartus\extlibs64\tbb\tbb42_20131118oss_altera\src\tbb\arena.cpp:105
    0x16867: tbb::internal::market::process + 0xf7 (tbb) at d:\sj\nightly\17.1\240\w64\acds\quartus\extlibs64\tbb\tbb42_20131118oss_altera\src\tbb\market.cpp:479
    0x10eac: tbb::internal::rml::private_worker::run + 0x6c (tbb) at d:\sj\nightly\17.1\240\w64\acds\quartus\extlibs64\tbb\tbb42_20131118oss_altera\src\tbb\private_server.cpp:283
    0x1111a: tbb::internal::rml::private_worker::thread_routine + 0x5a (tbb) at d:\sj\nightly\17.1\240\w64\acds\quartus\extlibs64\tbb\tbb42_20131118oss_altera\src\tbb\private_server.cpp:240
    0x24f7e: _beginthreadex + 0x106 (MSVCR120)
    0x25125: _endthreadex + 0x191 (MSVCR120)
    0x154df: BaseThreadInitThunk + 0xf (KERNEL32)
     0x485a: RtlUserThreadStart + 0x2a (ntdll)

End-trace


Executable: quartus_fit
Comment:
None

System Information
Platform: windows64
OS name: Windows 10
OS version: 10.0

Quartus Prime Information
Address bits: 64
Version: 17.1.0
Build: 240
Edition: Pro Edition