Issue in stereo_dft_dec, low band spectrum energy difference between float and fixed point

With 23094e13, and this bistream :

799_ff_mic12_SbSb003_-stereo_24400_32.bit

Command line used: STEREO 32 bit syn (and MONO 32 bit syn)

We can observe that in the DFT stereo part of the file, some parts of the spectrum have wrong gain (see figure 1 and 2, at around 1.7s and 1.87s).

On the other hand, if we ask the decoder to output the MONO downmix, the gain difference between float and fix is not observed anymore

Locally, I got the output just after ivas_core_dec() and just before stereo_cna_update_params() for both fix and float decoder. When using the STEREO command, the synthesis after ivas_core_dec() don't exhibit major gain difference while the per-channel synthesis before stereo_cna_update_params() do.

Then the "only" difference is the call to the function stereo_dft_dec()