On visionOS 27 (27.0 Seed 4, 24M5326g), adding a ManipulationComponent to a single entity makes RealityKit remove the RealityView's ENTIRE content hierarchy from the scene and re-add it about 30ms later. Not just the manipulated entity — everything. Same app binary on visionOS 26: never happens. FB24092291.
Bisected on the same build and device:
two entities, neither with manipulation -> no detach add one entity with a ManipulationComponent -> detach, every time same entity, manipulation swapped for my own drag/rotate/ scale gesture handling -> no detach
Everything else is identical between the last two cases — same entity, same collision shape, same InputTargetComponent, same ViewAttachmentComponent, same scene, same view hierarchy. The only variable is whether the component is installed.
Setup: an immersive space containing a SwiftUI RealityView. One root entity added to the RealityViewContent in the make closure; all app content built as its descendants.
The detach is brief but not harmless: every entity in the hierarchy gets SceneEvents.WillRemoveEntity and then DidAddEntity, so anything keyed to those events runs a full teardown and re-add for content that was never meant to go anywhere. In my app that cascade is what makes the scene visibly empty and rebuild.
Nothing in my code removes it. Stack captured from a WillRemoveEntity subscription on the root — frame 0 is my callback, everything above it is framework:
SwiftUI (AttributeGraph StatefulRule.withObservation ...) -> RealityFoundation -> CoreRE -> entity removal
Ruled out before landing on the component: make runs exactly once, the root re-enters a scene with the same ObjectIdentifier (not a re-host), the hosting controller is never deallocated, there is exactly one RealityViewContent.add(_:) in the whole app, and with Self._printChanges() in the view's body the detach happens in an update pass where the body is not re-evaluated at all. Also ruled out: transient overlay UI (suppressed entirely, still detached) and entity count.
Workaround if this is biting you: skip ManipulationComponent on 27 and handle drag/rotate/scale yourself. That is what I am doing for now.
If you are debugging something similar: SceneEvents.WillRemoveEntity also fires when an entity merely leaves a scene, so a teardown-looking log is not proof anything was destroyed. Check whether make ran twice and whether the scene identity changed before suspecting your own code.