It would have to be a few years ago. I posted some photos maybe 3 years ago when they did the 10th hole and they only had 2 or 3 holes left. I know they did the 5th after the 10th hole.
If I recall, most of the work was done in house with the assistance of a company named Bunker Masters. They spent a huge amount of money, every bunker lined with a fiberglass type of material so that the edges would stay intact forever.
I found the following on the web:
"The material (Stabilized Bunker Seal) was used in the bunkers at Cypress Point during their recent golf course restoration. It is a combination of decomposed granite, Stabilizer (a natural plant product that acts as a glue) and plastic fibers that act as miniature rebar. These materials have been used in the construction of cart paths, parking lots and sports fields for many years. The company, Bunker Masters Inc., out of Milpitas, installs Stabilized Bunker Seal, a product supplied by Stabilizer, Inc., of Phoenix, Ariz".