Sip usereqphone = yes does not add user=phone in From header

Asterisk Asterisk General
2

I have hit the same problem here, with user=phone being added to the invite sip uri, the TO sip header but not the FROM sip header.

Did you, or anyone, have a pointer as to what causes this behaviour, and how to fix it?

I can see another old request with the same problem, but no answer, so hoping that I can get a bit more success. See User=phone in FROM header field of uri-parameter of SIP URL

Thanks in advance