T48G Phones not disconnecting on Auto Answer for Intercom

[telone]

Hi Flora
Thanks for reaching out
This is happening on extensions that are VPS and BLF is set to each extension- also in FreePBX (server -extension setting i set to Internal Auto Answer =Intercom)
When I look at the CDR its showing *80xxx =*80 is the feature code for Intercom prefix
I have tested other Yealink phones and the same setting does not set call as a *80xxx. They just dial the ext number (the CDR show it is just a dial not a *80xxx) and the auto answer on intercom and it open the path and if either party hangs up it releases the call.
These two stations that are the problem if ext 100 calls ext 101 with the DSS/BLF key when ext 101 leaves the call ext 100 stay connected ( just like if it was connected to conference bridge and when you press the speaker key or handes(pickup and hangup) it then terminates call.
That is the issue that I am trying to resolve-1 what is causing it to become a conference call and why if called extension hangup why is the caller party stays active 2-If I dial *80xxx manually it either party disconnects both ext disconnect