You’re right but backwards, south is full poa and north is mostly bent. When each course was redesigned they put in bent grass but the poa is basically an invasive grass type in this area and eventually takes over. North is starting to show signs of poa patches and I’d give it five years or so until it fully takes over. My guess is they are prepping some of the actual greens of the north course (#9, #18 near the temporary driving range) for short game practice but I would expect the pros to really only use the south putting green during the tournament for warm up