Assertion fails after searching in Project -> AssetStore on opening Show in Asset Store.

1. Open Unity.
2. In Project search:
- enter something like "texture".
- in Search drop-down select Asset Store.
3. In search results click some of objects and click on it with RMB - "Show in AssetStore window" option appears.

The AssetBundle 'Memory' can't be loaded because another AssetBundle with the same files is already loaded.
UnityEditor.EditorApplication:Internal_CallUpdateFunctions()
fails.

Also assertion fails:
!dest.m_MultiFrameGUIState.m_NamedKeyControlList assert

Expected result: No errors appear.
Actual result: Errors appear.

Reproduces in 5.6.0f3, 2017.1.0a6.
Does not reproduce in 5.5.f3.