It's been a year since I saw it, but on my last visit, the poa annua was starting to take over the greens at Pacific Dunes.
It's not a huge problem there, because it doesn't get hot enough on the coast to kill the grass, and it's pretty hard to overwater the course on that sandy base. However, the transition from fescue to poa will be a difficult process, until they decide it's too far gone and just let the poa take over.
It's really just a combination of age and traffic. The first two courses have seen a lot of play and a lot of compaction from golfer's feet -- 40,000 golfers annually PLUS caddies PLUS all the staff play that takes place off the clock. As at Ballybunion and Lahinch, it's hard for the fescue to take that sort of relentless onslaught. One of the benefits of Old Macdonald was the thought that even if the overall # of rounds did not grow by 30% as a result of adding the fourth course, reducing the pressure on Bandon Dunes and Pacific Dunes would be a huge plus.