Sudden drop in comfort noise for fx enc at 24.4kbps stereo DTX
# Basic info <!--- Add commit SHA used to reproduce--> - Encoder and Decoder (float): db364042fba738d5d0f9823c047e75edea62bae7 - Encoder (fixed): d3f2d47ab8c8135bc56a7c5eb27ed7e8997f210d # Bug description flt_enc -> flt_dec: ![Screenshot_2025-06-20_at_17.32.17](/uploads/ceedef80396f5ebc4776703dda2db8d3/Screenshot_2025-06-20_at_17.32.17.png) fx_enc -> flt_dec: ![Screenshot_2025-06-20_at_17.32.20](/uploads/c5abacda2266c3958dd5e672affee047/Screenshot_2025-06-20_at_17.32.20.png) Above spectrogram shows a drop in the generated comfort noise when using the fx encoder. This indicates that the payload of the SID frame might already be incorrect. The float version also has a drop of one frame. This is also not correct and should not be mimicked by the BASOP code. # Ways to reproduce <!--Commandline or script--> ```bash ./IVAS_cod_fx -stereo -dtx 24400 32 ltv32_STEREO.wav bit_fx ./IVAS_dec_flt stereo 32 bit_fx out_fx.wav ``` <!--- Below are labels that will be added but are not shown in description. This is a template to help fill them. Add further information to the first row and remove and add labels as necessary.-->
issue