The Duowave Catastrophe was effectively an EM pulse that affected electronics throughout a big part of the galaxy. The Bottlenose Nebula was inside the affected space.
An infomorph species known as the Echo Mist was coming to ascendance, which for them involved inhabiting clouds of nanotech and exploring the galaxy in that form. As with many nanotech devices, they communicated via Duowave Pulses.
They began scanning a forming black hole. At the time it was a rapidly rotating collapsing star - not particularly notable to anyone outside of astrophysicists. Now it is quite notable, and named after them.
When exposed to the duowave communications of the Echo Mist, the pulses became distorted and amplified to a degree not expected by the Echo Mist - or by anyone else. As the star continued its collapse, the rotational speed of the star continually increased. This resulted in it "catching" its own duowave output and re-amplifying it along a new frequency spectrum.
The resulting "scream" spread outwards at light speed, a sphere of ragged duowave energy blowing out almost every electronic device within range. Worse, the nature of duowave pulses largely sustained it even over very long distances, even as a spherical emission.
The Echo Mist were only the first victims.
Nearby systems were knocked offline before anyone realized what was happening, but news spreads faster than light. Superluminal civilizations immediately began to plan for survival - usually by desperately retrofitting their electronics to survive the pulse.
Infomorphs and protoinformophs were largely unable to do this, due to the delicate nature of their computations. They fled ahead of the pulse or were destroyed. Either way, they left this area of the galaxy, setting back our understanding and integration of infomorphs considerably. Only recently have they become common again.
The pulse lasted for hundreds of years, only ceasing when the Echo Mist Black Hole finished forming, stabilizing its rotational velocity and finally letting the duowave pulse out of its endless cycle.
Effect on Subluminal Species
Without the ability to outrun the pulse, subluminal species were limited to adaptation... but most subluminal species were not made aware that the pulse was approaching. To them, electronics simply... stopped working. For hundreds of years.
This may explain why biotechnological species seem to dominate the Bottlenose Nebula. Species like the Transition Protectorate and The Starlifters are far more common in this 'cycle' than they have ever been in the past, perhaps because of the indirect advantage of not having to compete with electronics-oriented species.
But only one Bottlenose-indigenous species is known to have directly benefited from the Duowave Catastrophe: the Solko.