Unbound restarting on interface up/down, previous forum solutions not working

[HerkomerKlamm]

My Unbound is restarting frequently, even every 15 seconds under heavy load. This is being caused--I believe--by my WAN interface flapping. That is a separate issue I am trying furiously to resolve, but in the meantime I am trying to get Unbound not to restart with every WAN flap.

I have seen in previous forum posts that this can be caused by having DHCP registration enabled in Unbound. I do not have it enabled. I have also seen that it can be caused by having specific interfaces specified for Unbound to listen on. I did have this set, but on seeing the recommendation to use the recommended setting of 'all' (no specific interfaces set), I configured it that way. But the problem persists.

Any other ideas why Unbound is repeatedly restarting?