Switches disconnected from Mist due to name resolution no longer working. The name-server config still existed under "groups top system name-server" and applied, but it seems is not taking effect.

user@root> show configuration | display set | match name-server

set groups top system services name-server 192.168.0.130 routing-instance mgmt-junos

set groups top system services name-server 192.168.0.131 routing-instance mgmt-junos

set groups top system services name-server 192.168.0.132 routing-instance mgmt-junos

set groups top system services name-server 1.1.1.1 routing-instance mgmt-junos

By adding a cli command of "set system name-server 1.1.1.1" directly to the switch allowed name resolution to start working again and the switches rejoin Mist.

First 3 DNS servers fail to respond to DNS queries, switches disconnect from Mist, by adding the DNS configuration at global configuration level cause the switch to reconnect to Mist.

This is expected behavior, Junos documentation about the DNS explains it:

"To configure multiple name servers, include a maximum of three address options. The system uses only the first three configured addresses even if you configure additional addresses."

https://www.juniper.net/documentation/us/en/software/junos/cli-reference/topics/ref/statement/name-server-edit-system.html