Stereo Encoder: BWE artefact at 48 kbps LTV
# Basic info
<!--- Add commit SHA used to reproduce-->
- Float reference:
- Encoder (float): f2eb9e0831ece72ec66a0c07e62d1f3302e2a910
- Decoder (float): f2eb9e0831ece72ec66a0c07e62d1f3302e2a910
- Fixed point:
- Encoder (fixed): 7f488e0a12131c01a1b44b0d63c5c8bbea8dc950
- Decoder (fixed): n/a
# Bug description
For 48 kbit/s stereo encoding, there is a very outstanding BWE difference right at the beginning of LTV at 0:01.8:
BASOP:

Float:

From a perceptual perspective it's not super-critical, but it's so outstanding that it's probably easy to debug.
# Ways to reproduce
<!--Commandline or script-->
```bash
IVAS_cod -stereo -dtx 48000 32 ltv32_STEREO.wav ltv32_STEREO_48kbps_DTX.192
IVAS_dec stereo 32 ltv32_STEREO_48kbps_DTX.192 ltv32_STEREO_48kbps_DTX.wav
```
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issue