System Information
Operating system: linux 64-bit
Graphics card: nvidia geforce gtx-650

Blender Version
Broken: 2.80-953419c641a7 (blender-2.80-953419c641a7-linux-glibc224-x86_6)
Worked: (optional)

Short description to reproduce
Removing all collections from the object via the Context-object properties tab (orange square -- Property panel) results in the object getting deleted.

If the Outliner(View-layer outline), has the top node selected, 'Scenes' and the focus is not a collection, an object added inside the 3D-editor will then appear in the Outliner but will not be inside a collection.

Blender 2.8 beta supports creating objects without being in a collection, and permits moving an object(Outliner, View-layer outline) from a collection to the top 'Scenes' hierarchy, so by this observation.. removing the all collections from an object using the Context-object properties-tab should be possible without removing the object.