This is apparent when attempting to use a component that uses refs, multiple React instances appear to be introduced, at least during development. Unclear if it is actually being caused by development tools or not.
Thorsten Scherler first reported this as:
You can not use any dependency that uses @refs since of duplicate Reacts.
This branch shows an example of the problem: https://github.com/kzantow/blueocean-plugin/tree/victory-failure