Random behaviour of BWE at 32 kbps

With 30632c9d,

when decoding at 32 kbps, the BWE seems to have some random behaviour. As shown on the spectrogram (top: signal example, middle:float and bottom:Fix-point):

• Section A
  • BWE shows frame discontinuities.
• Section B
  • BWE exhibits only noise, while there should be a structured spectrogram.
• Section C
  • BWE energy is missing
• Section D
  • BWE matches almost perfectly the floating point

In the image below, it's the same synthesis with the core associated to it (top float, middle fix, bottom core). It seems the BWE has more issues when the core is ACELP (core==0) and TCX20 (core==1)

Can be re-created using :

bit

IVAS_dec STEREO 32 bit syn