Hi, Mr. Mierla
Yes.
It was through ngrep, in fact, I detected the source of the problem. It was not quite a bug anymore, but yes, it was a lapse of mine. My INVITE had the From and P-Asserted-Identity header fields. In this scenario our Telephone Carrier relies more on the PAI header to set the originating number because we using DID. That's why I was thinking that the assignment to $fU variable was bugged.
So that there is not any error in the Identification of the DID originator number, I decided to define the two fields:
$fU = $var(newUsername); subst_hf("P-Asserted-Identity", "/<sip:[^@]*@/<sip:$var(newUsername)@/", "a");
I solved the problem like this.
Greetings! Cleviton