Yes, braking in a left turn with tele forks or anything other then a setup leading link with front brake especially will cause the sidecar nose to dip. Weight transfer will increase and unload the rear wheel. Wheel lead will come into play in helping this situation but too much will have it's own downsides too. It is beat to brake prior to the turn in left or right handers when possible. Much can be learned by practicing with your own outfit.