Entering an instance LFG with spec switch

[doofus]

Would anyone know what events are fired when we enter an LFG instance and the game automatically switches talents for us when it teleports us in? Eg we are in tank spec and have queued as DPS so on entering the instance we are auto-switched to DPS.

We receive two ACTIVE_TALENT_GROUP_CHANGED event messages, but in both, calling GetSpecializationInfo() returns nil, nil etc

Maybe there is another message associated with auto-switch specs and teleport to/from instances ?