This knowledge base article explains the behavior observed when Multi-Node High Availability (MNHA) is configured on SRX devices operating in packet mode.

When MNHA is configured with an SRX device running in packet mode, the Cold Sync Status remains stuck in:
IN PROGRESS

Example CLI Output:
root> show chassis high-availability information 

Node failure codes:
    HW  Hardware monitoring    LB  Loopback monitoring
    MB  Mbuf monitoring        SP  SPU monitoring
    CS  Cold Sync monitoring   SU  Software Upgrade
 
Node Status: ONLINE
Grid-id: 0
Local-id: 1
Local-IP: 10.22.0.1
HA Peer Information:

    Peer Id: 2        IP address: 10.22.0.2     Interface: ge-0/0/1.0
    Routing Instance: default
    Encrypted: NO     Conn State: UP    
    Configured BFD Detection Time: 5 * 400ms
    Cold Sync Status: IN PROGRESS 

Services Redundancy Group: 0
        Current State: ONLINE
        Peer Information:
          Peer Id: 2

SRG failure event codes:
    BF  BFD monitoring
    IP  IP monitoring
    IF  Interface monitoring
    CP  Control Plane monitoring

Services Redundancy Group: 1
        Deployment Type: ROUTING
        Status: INELIGIBLE
        Activeness Priority: 200
        Preemption: ENABLED
        Process Packet In Backup State: NO
        Control Plane State: N/A
        System Integrity Check: COMPLETE
        Failure Events: [ BF ]
        Peer Information:
          Peer Id: 2
          Status : ACTIVE
          Health Status: HEALTHY
          Failover Readiness: N/A

Packet mode is not supported for MNHA because the jsrpd infrastructure depends on flow mode; since packet mode does not create flow sessions, no session state is available for synchronization, which prevents Cold Sync completion and causes the status to remain "IN PROGRESS."