When deploying an SRX chassis cluster with Mist, the way the Inventory devices are assigned on the Mist Dashboard matters.

If the cluster consists only of one node at the time of adoption, 10> min after assigning this single node to a site the node will reboot, load factory default config and delete all logs.

If the cluster has two existing nodes, after adding one single SN to a site the Dashboard will show 'AppTrack' installation failures.

In order to create a device that will be considered as a chassis cluster on Mist, the two SN corresponding to each node have to be selected on the Mist Inventory, if this is not done and only one device is selected, the resulting WAN Edge device will be considered standalone.

When this happens:

If only one node is present, Mist will detect that the connected device is in chassis cluster, disable chassis cluster on this device, and reboot it.

If both nodes are represent, Mist will install the 'AppTrack' license to only one of the nodes, meaning the App Database Installation on the 'secondary' node will fail.

You may find our documentation of the suggested process: https://supportportal.juniper.net/s/article/MIST-SRX-How-to-configure-SRX-chassis-clustering-with-Mist