Was it just surging or like a compressor stall or something? FOD like a bird ingestion or something?
I mean, Boeing has/had quality problems, serious ethical failures, but also birds exist.
(I’m not good at explaining this, maybe should have found an explanation online somewhere instead.) You know those stages of a combustion engine - intake, compression, ignition, exhaust, all happening in sequence in an engine’s cylinders? Turbine engines do them too, but in a straight line and constantly. The front of the engine is obviously intake, but compressor fans do the compression just using fast and powerful fans, no seals or valves needed. Ignition lights everything up, exhaust can just flow out the back. (It flows over some more fan blades that steal some power from the expanding gases and use it to keep the whole thing spinning.)
Unless something goes wrong with the compressor fan blades, that is. If compression is too weak and the ignited air/fuel mixture can flow back out the front of the engine, that’s bad. And yeah, it happens sometimes, with any engine. Almost never with both at the same time. (Both engines failing at once low to the ground is like a once in a generation thing, and yeah it’s really really bad. And really really rare.)
Devs make mistakes. We want to put up guardrails so mistakes don’t hurt us so much.
Please don’t deliberately line the guardrails with barbed wire.