How do I add a simulation model to a multi-part component in Altium?
Check if the lib really contains 2x op-amps. Most TI models contain only one opAmp with supply pins. Try to copy and paste it to have it so you have it twice in the model file. Then name pins of the two model instances as in your Altium symbol. If this does not work you could need a kind of wrapper which has all pins and the calls the two models