Destabilization

Early research into what would become known as Breach Phenomenon was frustrated by the literal vanishing of evidence -- not hidden by shadowy organizations (though that happened, too) but actual disappearance, before witnesses and on-camera. In some cases, such as the passenger pigeon plague , this happened at a molecular level.
Annoyingly, it was not entirely consistent. It generally happened in a few hours to do a day. It sometimes didn't happen at all, as was the case with a sample of tyrannosaur scat in Georgia, or with a newspaper returned from an alternate-universe Pennsylvania town. Sometimes, it took several days -- the only reason the three days dieoff didn't last weeks or months was because the actual viruses vanished, after reproducing thousands of times.
It is semi-determined that:

• Breachers can bring back items from natural breaches within some limits. (2 x BL)
• If a stable artificial breach is established, most objects, plants, and animals can cross freely with no risk of destabilizing; CERN has kept some samples from such stable breaches, measured to a femtogram, in sealed containers, and will issue an alert if there's any hint of a change in mass.
• There is substantial nervousness about destabilization occurring after months or years; if metals mined on Vulcan disappear in four, five, or ten years, buildings might collapse, ships sink, bridges vanish. This is the main damper on full-scale exploitation of many worlds; until the physics of breaches and destabilization can be understood to the 20th decimal place, this specter haunts most plans.
• Since 2010, natural breaches have produced items less prone to destabilization; more and more often, they last longer and are occasionally permanent. This seems related to the increasing risk of Dimensional Fracture

Manifestation

Things simply 'wink out'. It appears to take place in a planck moment, and infuriatingly, there is no other disturbance -- no air rushes in to the empty space. It is as if the object wasn't ever there at all. Effects remain. The object was there. Those who survived the three day dieoff had every trace of infection vanish from their bodies, but cells partially damaged by the virus, and immune cells created in response, remained.

Type

Natural