media profile producing 488 not acceptable here

Hi,

Acme Packet OS VM SCZ8.3.0 MR-1 Patch 7 (Build 292)

Oracle Linux branches-7/el7-u7 {2019-11-01T07:00:00+0000}

Build Date=03/13/20

we had a strange behavior on our access sbc:

1. some PBX are sending this type of sdp

m=audio 49442 RTP/AVP 8 101

a=rtpmap:101 telephone-event/8000

a=fmtp:101 0-15

a=ptime:20

--> as you can see no "a" attribut for PCMA media=8
--> no media profiles created
--> working fine

2. for a specific project, I created a media profile G711a

media-profile

        name                                    g711A

        payload-type                            8

        clock-rate                              8000

        req-bandwidth                           90

        frames-per-packet                       30

        parameters                              0-15

3. after creating it, the calls of the PBX presenting the SDP without "a" attribut were rejected with "488 Not acceptable Here".