radvd weird behaviour since upgrade

[ferryvanaesch]

Hi,

Since upgrading to 25.7 (on 25.7.5 at the moment) I noticed IPv6 not working properly anymore. I've ran this successfully for the last number of years. radvd seems to work fine for a few minutes after restarting the service, but then my browsers switch back to IPv4 a few (1-2) minutes later.
Has something changed in the config that I need to configure now?

[ferryvanaesch]

Seems I needed to add a firewall rule for the LAN interface to allow the advertisements to go through. Seems to be running for the last while anyway. So maybe the firewall logic has changed?

Edit: that was a red herring. It still stops working.