The simple thing would be to swap the lambda sensors around. You can also use carburetor cleaner or brake cleaner to tray to find the leak if there is one. If you're not familiar with how to do this. Start the engine. Let it idle. Spray the cleaner around where you suspect a leak. The rpm will increase if the intake is able to suck in the cleaner. You could also try a gasket maker or adhesive to help ensure a tight seal. If your adaptive map is maxed out you might want to consider clearing the adaptive map. Perhaps it is showing the code in error due to the maxed out maps. Just my thoughts.
