Teams Direct Routing SBC in media bypass mode assumes REFER

[b_sim]

We found a bug when enabling media bypass on our SBC, where we have chosen not to support transfer by REFER method. 

After setting media bypass to enabled, the Teams proxy is trying to use REFER for hold and transfers even though we do not allow it. When media bypass is disabled, it does not try REFER, and everything works correctly.

Does anyone know how to enable media bypass and preserve valid SIP behavior? (e.g. do not use REFER if it is not listed in the Allow header)

[#2]

@b_sim Any luck with this?

We're having some different REFER issues ourselves.  Without REFER, we get no ringback, as our Oracle SBC expects a REFER according to the docs during a call transfer.  So while the transfer works, the user hears silence.