An ongoing search for 140 professionals with expertise in AR isn't a blip; it's a concerted effort by Facebook to figure out and execute the technology as part of a larger effort, most likely related to the company's Spark AR augmented reality platform that is a potential revenue source when it comes to advertising and product placement.
The vast majority of Facebook's AR hires are being done at its Menlo Park, CA headquarters followed by Redmond, Washington.