Starting from JUNOS 21.4R1 a new feature is introduced that allows the configuration of the hold-time on the ae interface 

Due to some legacy configuration in their network, the customer is asking about the behavior of having the hold-time configuration in the physical members interface, ae interface, or in both physical members and ae interfaces, 
 

NOTE: When you configure hold-timer for ae- interfaces, we recommend not to configure the hold-time for member links.

• This new feature will not advertise the aggregate interface state transition from UP or DOWN until the hold-timer expires
• The hold-time that is configured in the ae interface level will not be passed to its member links 
• If hold-time is configured under the ae interface the timer value will not be showing in any of the operational commands and we need to rely on the configuration
• In case of the hold-time is configured in both members/physical and in ae interface which is not recommended as per our documentation, the behavior will be :  

1. First the hold-time for the minimum required links to change the aggregate interfaces state from/to UP or DOWN needs to finish 
2. Then the configured hold-time for the aggregate interface itself will kick in.