I have enabled the TOPOH module  with mask_callid enabled, but it's generating a new Call-ID for a BYE which gets rejected with a 481 downstream. If I disable the TOPOH module it works as expected.

Does anyone know where I should start looking? SIP-wise the initial BYE seems compliant.

This is Kamailio 5.5.3 on Debian 11

Thanks

Matthew