ipv6 - tunnelbroker - connectivity issues

[GreenMatter]

I have setup, in a few of my vlans, some time ago ipv6 through tunnelbroker.
It's been working fine until now. Still I can ping WAN hosts, unbound resolves AAAA queries:

% dig google.com AAAA       

; <<>> DiG 9.10.6 <<>> google.com AAAA
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 4210
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 1232
;; QUESTION SECTION:
;google.com.         IN   AAAA

;; ANSWER SECTION:
google.com.      40   IN   AAAA   2a00:1450:401b:804::200e

;; Query time: 2 msec
;; SERVER: X001:XXX:XXXX:4::1#53(X001:XXX:XXXX:4::1)
;; WHEN: Thu Feb 29 12:00:35 CET 2024
;; MSG SIZE  rcvd: 67

But any tests I do via browsers (Safari, Chrome), fail miserably. For example, https://test-ipv6.com/, says there's no ipv6 address discovered.
With exception of my OpenvPN road warrior connection. When I connect via VPN, all is ok. 
FW has of course ipv6 enabled and respective vlan also has rule allowing all "IN" ip4+ip6 traffic - as same as group openvpn interface. How to troubleshoot it???


EDIT:
It seems like I can think better when I write post :-). I had/have caching (squid, icap) enabled on couple of vlans. And this was filtering out my ipv6. Is it possible to configure caching for ipv6?