The take of the author Paul Bryan:
UX strategy and agile UX are neither compatible nor incompatible. In an agile shop, UX strategists have to get ahead of the curve and do their work before agile development starts. They need to coach UX team members and convince others on a product team to value the guidance that UX strategy brings to digital design efforts and to follow the strategy in making design decisions throughout the life of the program. Once the agile train gets rolling, it may be very difficult to introduce strategic considerations.