From Gentoo Wiki
1. If you have compiled bridge netfilter into your kernel Is it correct that it's only the case when you have BRIDGE_NETFILTER=y in the kernel config? If it is the case then there's also another workaround to change that kernel config option to BRIDGE_NETFILTER=m.
2. Also, what do you mean "all network traffic from the bridge is filtered by the kernel for routing" exactly?
3. I corrected your issues with url and file inside you note changes. But it would be better for you to specify the exact kernel option in the brackets or smth like that as I asked above.