Encoder crash for McMASA 5.1 at 13.2-32 kbps WB encoding

Basic info

• Encoder (fixed): ae6313fd
• Decoder: N/A

Bug description

The fixed point encoder crashes with an assert:

Assertion failed: (0), function L_shl, file basop32.c, line 2580.

Ways to reproduce

Input vector has been uploaded.

./IVAS_cod_fx -mc 5_1 -max_band WB 13200 48 bm2aa1s12_48.10dB.wav bit

The same issue occurs for 16.4, 24.4 and 32 kbps. Additionally the same error about IGF as in #1129 (closed) is reported on the commandline.