DNS resolution takes ages after failover

[ricksense]

Hi,

I set a dual WAN failover on my Opnsense which is installed on a laptop.
The main WAN interface is a wifi dongle which works [almost] perfectly.
The second WAN is an ordinary ethernet interface.
I need this setup since the OPNsense device is meant to be a portable firewall/router.
The failover works, it switches to the second WAN if the primary goes down, and back to the main WAN when it is up again, even though there is an issue with the wifi re-connection as I wrote here in this thread already:

https://forum.opnsense.org/index.php?topic=37858.0

However, the DNS resolution (unbound is running) takes ages when the connection switches back to the main WAN (wifi), but no issue with the dns resolution when the connection switches from WAN1 (wifi) to WAN2 (ethernet).

Why?

Thanks