During the investigation of case 03831304 in NMT-1157, it was discovered that NetworkManager fails to reactivate VLAN interfaces after the parent device reappears following a temporary unavailability. This behavior results in network access problems, as the connections remain blocked even after the parent device returns, preventing the VLAN interface from being reactivated.

To resolve this gap in handling of device reappearance, there is a proposal to implement a mechanism in NetworkManager that will automatically unblock and retry activating connections when the parent device becomes available again. This will ensure that VLAN interfaces and other connections are correctly reactivated and prevent network disruptions.