Problems getting static IPv6 to work on VLANs

[AS5]

Hi,

I do have a problem with configuring IPv6 on VLANs, most likely due to missing IPv6 knowledge.

On the WAN interface, I get a static IPv4 via PPPOE, and a static IPv6 net (/60) via DHCPv6 from my ISP.
On the LAN interface, I got IPv6 working. I used static IPv6 here (one /64 net).
On this LAN interface, I do have in addition 2 VLANs - one for guest WiFi, one for IOT. For the GuestVLAN, I also configured a static IPv6 net here (another /64) net, but when I'm connected to the guest WiFi, I don't have any IPv6 connectivity.

I'm using DHCPv6 to dynamically assign IPv6 adresses to clients, Router Advertisements is set to "Managed" for both LAN and GuestVLAN.

When I look at clients connected to the default LAN, they get an IPv6 address from the network I defined on this interface, and an ULA (fd6c:.
Clients on the GuestVLAN only do get an IPv6 address from the static IPv6 net I defined on this interface, but no ULA. Also, the gateway (fe80: is the same as on LAN. Not sure if this is supposed to be like this?
I don't know why my clients don't get an ULA address in the GuestVLAN, even though the configuration for the interfaces, DHCPv6 and RA is the same (except for different networks of course); also, I don't know if I would need an ULA address at all.

Anyone has a clue what I'm missing here?
Thanks!

PS: IPv4 is working perfectly on all VLANs in this setup.

[Patrick M. Hausen]

Did you add IPv6 related firewall rules to your VLANs? By default there aren't any - which leads to implicit deny.

[AS5]

Yes, sorry for not mentioning that - I cloned the existing IPv4 rule on the VLAN, and changed protocol to IPv6.