Leaks left side underneath.. only on rinse cycle

If the washer is leaking water the front door boot seal might have a tear or rip and is letting water leak past. The boot seal can be replaced. This part can tear when the washer is overloaded. This is a common repair.
Also check the drain hose. The most common places for the hose to spring a leak is from the connection to the pump out to the back of the washer. Another common occurrence is when the washer gets pushed too far back against the wall.

Pump