From the federation docs:

The status.discoveryStatus.active.remotes field shows that istiod in the peer mesh (in this example, the green mesh) is connected to istiod in the current mesh (in this example, the red mesh).

This field appears when connection between serviceMeshPeers is first established, but disappears after some time (~10m).

Expected Behaviour

This field should remain present to allow users to verify that istiod in the remote mesh is connected to istiod in the local mesh. Alternatively, the docs should state that this field is short-lived.