Resolution:
Failover does not need to occur for this parameter to have meaning.

When the server closes a client connection, if the client is using FT URLs, the ft_reconnect_timeout value still applies.

The ft_reconnect_timeout is the time a server (either active or backup becoming active) will hold on the connection logic information for a client that created a connection using FT urls (that is at list 2 urls comma separated) and that has been disconnected (not explicitly called connection.close()). After this ft_reconnect_timeout interval elapses, the server will remove all connection information for that client (and print the "due to FT timeout" connect tracing if enabled).