Failover not returning to tier1

[larxxor]

Hi, I need info on how to make gateway group return to tier 1 after incident.

I have a gateway group with tier1=fiber and tier2=metered LTE

When running normally all traffic goes thru tier1 fiber. Then there was an outage and the gateway group started to use tier2 LTE as expected. So far everything good.

But then tier1 fiber came back online, shows up as working in dashboard. The traffic remained on tier2 LTE. I left it be for a few hours, nothing changed.
Eventually I fixed by manually disabling LTE gateway.

How do I make it switch back to the tier1 gateway from tier2 when it is back up? The guides I read regarding failover does not seem to mention this.

Br Lars