I've found this below?.
This BUG is printed because this node received a FACILITY message on a dch, asking us to perform TAT. But at our node TAT is not configured as an RCAP, therefore we print the bug4046. remove tat from far end dch rcap.
NB: TAT requires an MSDL-based DCH for the feature to work. The NTAK79 PRI card on small systems will not support TAT.
Meridian 1 / CS1000 ISDN PRI TAT feature
The system only supports Trunk Anti-Tromboning on the Multi-purpose Serial Data Link (MSDL) card for D-channel handling.
Note: Small Systems and CS 1000S systems only support the Trunk Anti-Tromboning feature on the NTBK51BA D-Channel Daughterboard for D-channel handling with PRI. The NTAK79 2MB PRI card does not support TAT.
To support the Trunk Anti-Tromboning feature within a dedicated ISL/VNS configuration, an NTAK02 (minimum vintage BB) Serial Data Interface (SDI)/D-channel (DCH) circuit card must be used.
See the ISDN Primary Rate Features NTP for a full description of Trunk Route Optimisation and TAT
All the best
Firebird Scrambler
Meridian 1 / Succession and BCM / Norstar Programmer in the UK
If it's working, then leave it alone!.