What exactly are the THR TARGET feedback and ATHR EPR TARGET limited to the corresponding EPR TLA? And why exactly would they differ in this situation?
1. You have ATHR on and SPEED managed mode---> Thrust target to maintain the chosen speed
2. you take the thrust lever out of the CLB detent --->TLA reduces the
maximum EPR possible between max CLB EPR and Idle EPR = A/THR EPR target.
3. You have an A/THR disconnect after 1.8 seconds if 2 becomes too inferior to 1, meaning that A/THR can no longer maintain the managed speed.
You also get the A/THR Disconnect warning.
That's apparently the disconnection factor on this landing.