PAXboy, I guess you aren't up on maintenance and production jargon.
Quality Escape is a professional's term that applies to cases like this, and it isn't limited to Boeing-speak.
Here is some reading material for you to take a look at.
The-Analysis-of-Quality-Escapes-in-the-Aerospace-Defense-Industry.pdf (ren-services.com)
In gross terms, quality escapes are nothing more than inability to manage the details. Not surprisingly, the root causes of numerous quality escapes are found in the flow and interpretation of technical requirements. These root causes often take the form of ambiguity in the original requirements, failure to adequately evaluate the results of requirements interpretation, or simply overlooking the requirements.
And a bit of motherhood
In fact, the current quality imperative across all industry sectors has focused a harsh light on quality escapes.
Six Sigma has become the stated objective of prime contractors and their suppliers across the aerospace supply chain. Industry sponsored organizations which formulate quality policies and procedures have instituted strict standards (e.g., AS9100) which exceed ISO in their requirements.
This is particularly true in areas such as management of characteristics, control of manufacturing processes, adherence to specifications, and configuration management. Aerospace prime contractors are increasingly requiring their suppliers to achieve AS9100 registration.
The industry is also applying the first article inspection methodology prescribed in AS9102 which places strong emphasis on characteristic accountability. This emphasis is largely based on the recognition that many quality escapes happen with the very first production unit as a result of an inadequate first article inspection. {Renaissance Services White Paper: The Analysis of Quality Escapes in Aerospace & Defense 2} With all of this emphasis on quality, the continued occurrence of escapes is a driving factor in the establishment of programs such as e-LINCS. While AS9100 and related standards seek to legislate a certain level of quality behavior, the tools needed to ensure confidence in their compliance are largely absent from the primes and their supply chain.
The Qantas A380 flight over Malaysia (much discussed on PPRuNe) whose RR/Trent turbofan lost a turbine disc was, all said and done, a RR Quality Escape. (Investigatore eventually found out the root cause for why the lube line failed which led to the chain of events that resulted in the turbine disc leaving the aircraft...uncontained...)
(In comparison, the MCAS mess was a combined design and systems training system error, or at least that how I'd categorize it).