P1 MTA bind X.224 COTP packet - where does [Destination reference: 0x2c3d0000] come from

P1 MTA bind X.224 COTP packet - where does [Destination reference: 0x2c3d0000] come from?

I have working X.400 p1 connection from a 2010 code base and we are upgrading it to our current code base. The remote side responds with a bind-busy now.

In my X.224 COTP packet on the old working connection "[Destination reference: 0x00000] is indicated. On the non-working connection, a non-zero Destination reference is indicated.

Where does the wireshark get this information from? - it's not part of the COTP packet. It is also enclosed in square brackets.