He is an erratic fellow whose actions are usually completely unpredictable.

他是一个古怪的家伙，他的行为通常是完全无法预料的。

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While they may report the act itself, they should also be aware of actions that could be an indicator, such as unusual conduct or erratic emotional behavior in a coworker that could indicate a problem.

FORBES: Intellectual Property Theft: Beware The Enemy Within