More SLS issues:
New SLS booster design suffers anomaly during test - SpaceNews
A new version of the solid rocket booster being developed for the Space Launch System experienced an anomaly during a test firing in Utah June 26.
A little more than 100 seconds into the test, exhaust appeared from come out from the side of the nozzle. Seconds later, debris scattered from the vicinity of the nozzle, as seen in NASA’s webcast of the test.
While this is a significant change to the solid boosters (carbon composite casing vs. the existing steel construction), this is still a pretty big 'whoops' for something that was supposed to be based on 'mature' technologies.