Glitch when stereo is switching from TD to FD
# Basic info
<!--- Add commit SHA used to reproduce -->
- Float reference:
- Encoder (float): b4a17ad4
- Decoder (float): b4a17ad4
- Fixed point:
- Encoder (fixed): ffa2d613
- Decoder (fixed): b4a17ad4
# Bug description
When the codec is going back from TD to DFT, a glitch can be heard in the fixed point version (\~4.55s).
In the following figure, from top to bottom :
- floating point left channel
- floating point right channel
- fixed point left channel
- fixed point right channel
- floating point element mode
- fixed point element mode
{width=950 height=598}
# Ways to reproduce

<!-- Commandline or script -->
```bash
IVAS_cod -stereo 24400 48 G6S2.c01.wav bit
IVAS_dec STEREO 48 bit syn
```
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issue