Hello,
1. After you power off the board on which the VRRP backup group resides, the VRRP module deletes the VRRP backup group and its configurations, including the configuration of associating VRRP with NQA.
2. After you delete the NQA test instance, the NQA module notifies the VRRP module of the deletion event. Because the VRRP backup group has been deleted, the VRRP module does not process the deletion event.
3. After you power on the board on which the VRRP backup group resides, the VRRP module enters the configuration restoration procedure. By default, the NQA configuration is restored after the global and interface configurations are restored. Therefore, the VRRP module directly restores the configuration of associating VRRP with NQA without checking whether the NQA test instance exists during configuration restoration.
I hope this helps.