Decoder crash for MC51 at 48kbps FER in decoder_tcx_noisefilling_fx()

The fixed point decoder crashes in basop32.c:3481 with an abort for one of the verification test items:

Frames processed:       [1]    57924 abort      ./IVAS_dec_fx 5_1 48 out/mc-5_1--bm2ba1s07--48000.fer.192 

Steps to reproduce:

./IVAS_cod_flt_ref -mc 5_1 -max_band FB 48000 48 MC-5_1/proc_input/bm2ba1s07.wav out/mc-5_1--bm2ba1s07--48000.192
eid-xor -vbr -fer out/mc-5_1--bm2ba1s07--48000.192 error_patterns/mc-5_1--bm2ba1s07--48000_ep.192 out/mc-5_1--bm2ba1s07--48000.fer.192
./IVAS_dec_fx 5_1 48 out/mc-5_1--bm2ba1s07--48000.fer.192 out/mc-5_1--bm2ba1s07--48000.fer.dec.fx.wav

Float reference SHA (_flt_ref): d9fdb374

FX binary SHA (_fx): 2470528b

Error pattern file: mc-5_1--bm2ba1s07--48000_ep.192

Bitstream can be shared upon request.