Water is a byproduct of the fuel combustion process. Generally it exits the tailpipe as vapor. That a little condenses to liquid is not a surprise or a problem. With that said, generally water droplets are visible at the end of the tail pipe, not generally in the middle.
I think a bigger question is “Does this joint leak exhaust fumes when the vehicle is running?” I'm concerned that the droplet at that location indicates an exhaust leak. But that's easy to test. It will require a helper. Start the car, have the helper use a rag and GENTLY stop the outflow of exhaust. Just do this for a second at a time. You are not doing the banana up the tail pipe trick, ala Eddie Murphy Beverly Hills Cop. Don't do that. Its just a momentary test. When that happens, does this joint leak exhaust?
Oh, yeah... Safety Safety Safety. You will be able to hear the leak, even if you are laying on the ground three feet away. Don't get underneath a running car. Never a good idea.
Its totally possible that the gasket needs replacing to ensure a tight exhaust seal.