The UX community seems to struggle with Agile. They seem to want a special approach called Agile UX to resolve this struggle. As this quote states:
"Agile UX describes update of Agile Software Methodology with UX Design methods." 
I am not sure how such a wild statement of being able to 'update' Agile can be true and this article will show that there is no such thing. Agile UX is a misnomer.
From the many articles on the web UX professionals seem to be historically Waterfall people in their mindset. Which is why they struggle with Agile.
A classic example of this is whereby the UX practitioner works outside the team performing research (analysis) and design outside of the teams inspect and adapt feedback loop.
"UX Must Work at Least One Step Ahead of the Sprint" 
Not within the Sprint as part of the Agile team. Also retrospectives with the team seem not to be practiced within the UX community. This is akin more to mini-waterfall than Agile.