Xlite sending 2833 DTMF but Asterisk not registering

I see my Xlite client (v3.0 build 47546) sending 2833 to Asterisk (v 1.6.0.5) using wireshark both ends negotiate payload type 101 and I see the 2833 RTP packets.
For both my trunk and user peers…I have dtmfmode=rfc2833 and canreinvite=no.
When I debug the channel (and send DTMF), this is the only stuff I see.
<< [ TYPE: Null Frame (5) SUBCLASS: N/A (0) ] [SIP/amer-sbc-09af7290]
<< [ TYPE: Null Frame (5) SUBCLASS: N/A (0) ] [SIP/scott-b7906b90]
<< [ TYPE: Null Frame (5) SUBCLASS: N/A (0) ] [SIP/amer-sbc-09af7290]
<< [ TYPE: Null Frame (5) SUBCLASS: N/A (0) ] [SIP/scott-b7906b90]
<< [ TYPE: Null Frame (5) SUBCLASS: N/A (0) ] [SIP/amer-sbc-09af7290]

I can receive DTMF on an Asterisk application, but I believe this is picked up inband even tho Xlite is sending as 2833 as well.
[Mar 18 02:06:20] DTMF[23654] channel.c: DTMF end ‘1’ received on SIP/scott-b7907250, duration 0 ms

Any thoughts on where to go from here?
Thanks
Scott

This is either a direct response to RFC 2833 signalling or is down stream of any DTMF detection, so doesn’t represent evidence of inband decoding.