I don't see anything wrong in the traces.

First call (the one you flagged as success), is an incoming call on the ISDN link, almost immediately after the call is connected to the SIP end, FreeSWITCH receives 9199 from the RTP stream, and 71 from the TDM end. Those DTMF digits are passed from RTP to TDM and viceversa as expected. The call is then finally hung up

Second call (the one you flagged as failed) is pretty much the same, the DTMF 9 that you see is in the RTP wireshark trace, so there is nothing wrong here. That DTMF is there. The other end is sending that 9, the only difference is that this time the far end of the TDM side hangs up the call almost immediately after re-generating that 9 received in the RTP side into the TDM side.