Spectral gaps starting from mid-frequency range for MDCT-stereo 48kbps with +10dB input signals

Basic info

• Float reference:
  • Encoder (float):b09a7f47
  • Decoder (float):b09a7f47
• Fixed point:
  • Encoder (fixed):b4a8a48f

Bug description

For input signal level +10dB there are spectral gaps observed. It seems there is an attenuation for BASOP output around frequencies 8-10kHz and then for the IGF region the spectrum is different with several spectral gaps in various frequencies as can be seen from the spectrogram

and float for reference

For e.g. frame 0.820 s one can clearly see the attenuation for the said frequencies and then for the upper frequencies float and BASOP diverge:

Edit, I found a second item (am1aa1s14) with the same issue, most prominent frames starting from frame 0:05.880. Also uploaded in the same folder.

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1312

/IVAS_cod -stereo -max_band FB 48000 48 ap03a3s01_48.10dB.wav out.192
/IVAS_dec stereo 48 out.192 ap03a3s01[10dB].dec.wav