I have two dover composites that overall run fine but I'm having an intermittent problem with car two dropping the hall when it arrives to the landing on all intermediate floors. They are 6 stops and both units will answer call at top and bottom landings with no problems. At intermediate floors both cars will answer up calls just fine. Down hall calls however only elevator 1 will answer calls with no issue. Elevator two will answer the call but doors will not open and gong/ hall lanterns do not work as well. It will drop the call when it arrives. Once I press the down call again after its dropped elevator 2 will answer it being that it's already there. Car calls on both cars work fine. Limited experience on these units and an incomplete set of prints is an issue also but that's another story. Any tips would be appreciated