Bitcoin Core will happily spend RBF marked inputs it doesn't avoid them much less prohibit them.
Perhaps you're being confused by the fact that it will not spend an unconfirmed input created by a third party? Or maybe you have spendzeroconfchange set off or only have long-chain unspents?
so, I checked my router whether the port number(48302, 44660) is opened or not but, no any port is currently open.
They don't appear open because those ports are not always open listening for incoming connections. Rather those ports are bound to temporarily by the forwarding software which then initiates the connection to your computer. As soon as the ...