IPv6 breaks after a while and stays DEAD after upgrading from opnsense 25 to 26

[DWM89]

Hi!

I was running opnsense 25 for a good while and everything worked fine, now i tried to update to the current version 26.1.11_10 and all seemed fine at first.

I still had to manually tell my WAN interface to reload so I could get a DHCP lease from my ISP but then I got an IPv4 address and an IPv6 address and routes/dns and I was finally happy (I tried upgrading from 25 to 26 twice in the past with the same result as now!).
i could ping IPv4 and IPv6 hosts and generally use IPv6 sites normally.

Then, a few hours later (maybe 2 or 3) i realize that my IPv6 is not working anymore!
But I still have an IP...forcefully renewing the WAN interface didn't help.

IPv4 traffic still works like a charm.

the last 2 times I tried this upgrade I ended up ditching 26.1 and reverted back to my older opnsense 25 because i couldn'T solve the problem.
I am annoyed by this because it is obviously something that changed from opnsense 25 to 26 since when i revert to a backup from before the upgrade it works again with no problem.

On a side note:
I get a static public IPv4 and a static /56 prefix from my ISP
EDIT:
my configuration:
opnsense VM running on TrueNAS scale with dual intel i-226 NIC directly passed through to the VM
previously working version: 25.7.11_9 (Commit   2e9ac2def)
I have WAN and LAN configured on the 2 NICs, WAN DHCP on v4 and v6 (DHCPv6)
LAN uses Track WAN Interface for v6
I use ISC-DHCP for lan addresses and unbound for dns resolving

Could someone PLEASE help me with that issue?

Best regards

[meyergru]

You do not tell anything about your IPv6 setup:

DHCPv6 or SLAAC? Which daemon(s) for both? Do your clients still get an IPv6 assigned? What gateway do they get?

[DWM89]

Well actually I thought I did say: DHCP (so for v6 its DHCPv6 on WAN) and track interface on LAN

I don't get a v6 IP on my LAN interface after the v6 breaks and the ipv6 traffic on connected devices to the LAN interface doesn't work either

[meyergru]

That does not answer how you distribute the IPv6 on your LAN. You can do that via DHCPv6 or via SLAAC, with different daemons for each.

But FWIW, if your LAN loses its IPv6, then that seems to be the problem. You should set your LAN interface to "Identity assosication" instead of "Track Interface".