Firmware version: Any
It's odd that only the specific number would hava the issue. The call flow goes through like the following:
S-Series PBX>>>>Peer Type>>Avaya>>>>SIP trunk
The PCAP log shows the failed call using different codec in RTP direction. It's like the codec negotiation but not totally. As both side PBX have insisted their codec priority.
As Avaya PBX use ulaw as priority. Then just put ulaw as the first priority in S-Series PBX.