Longhorn volume is degraded, while all replicas are running

I have a Longhorn volume that should have 3 replicas. I logged into the Longhorn UI and noticed that the volume was “Degraded”. When looking at the volume, I saw that there were 3 replicas all “Running” but only one was blue, two were grey, and the health was “Degraded”. I deleted one of the volumes, and LH automatically rebuilt it, and shows as Healthy, but the 3rd replica is still grey. What can cause it to get to this state, and why did LH not self-heal the volume?