That would be 6.
Nope, no managed switch in my net.
Anyway, this all doesn't matter, because the problem exists even without my custom vlan configuration, when I just try to forward between br-lan and wlan1-1.
I am not sure if it is connected, but sometimes the devices are not working well with low vlan ids.
Can you try to use higher Vids like this one here?
I changed vlan ids 2 and 3 to 200 and 300, respectively (vlan id 1 wasn't changed in the example). No visible effect.
As I said, the problem was already there when I hadn't bridged wlan1-1 with ethX.Y and was using only wlan1-1 with no mods to the switch config at all.
I am out of ideas unfortunately 