Multi-frame attenuation for MDCT-stereo 48kbps with input +10dB
# Basic info
<!--- Add commit SHA used to reproduce -->
- Float reference:
- Encoder (float):b09a7f47a1bc3834f69b23a7337059451f5e7e9a
- Decoder (float):b09a7f47a1bc3834f69b23a7337059451f5e7e9a
- Fixed point:
- Encoder (fixed):b4a8a48f
# Bug description
There is an obvious attenuation for this item for frames from approx. 5.6s-5.8s as can be seen:

and the float version for reference:

It should be noted that the differences in the two versions are large.
# Ways to reproduce
Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1313
<!-- Commandline or script -->
```bash
./IVAS_cod -stereo -max_band FB 48000 48 dm1aa1s12_48.10dB.wav out.192
./IVAS_dec stereo 48 out.192 dm1aa1s12[10dB].dec.wav
```
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issue