>"We reported in October 2018 that CoreStage production is the primary factor contributing to overall SLS launch delays due to its position on the critical path
and corresponding management, technical, and infrastructure issues driven mostly by Boeing’s poor performance.
Boeing’s software development for the ICPS is also an ongoing concern as final modification of the software cannot be
made until NASA finalizes the Artemis I mission requirements. Additionally, with regard to Northrop Grumman’s
Boosters contract, numerous incremental contract modifications and the lack of a NASA appointed on-site technical
monitor have contributed to an administrative burden on NASA management and issues with monitoring contractor
performance. Moreover, both Northrop Grumman and Aerojet have experienced technical issues, with problems
related to the Booster’s Propellant Liner and Insulation and development of RS-25’s new Engine Controller Unit proving
difficult to overcome. "
Artemis final audit report dropped today, they're not being particularly diplomatic.
https://oig.nasa.gov/docs/IG-20-012.pdf 
