The end to the partial leave comes as questions linger over revelations that Rubin's departure from Google came after an investigation ruled that he's been involved in an "inappropriate" relationship with a subordinate. Rubin's spokesperson has maintained that it was a consensual relationship and nothing wrong took place, but the woman had filed a complaint with human resources that led to the investigation. There's no evidence linking Rubin's recent leave to the Google story, although the timing has certainly raised eyebrows.

Without details of what the complaint entailed, it's difficult to know just how much of a cloud this casts over Rubin's work at Essential. You can safely presume that concerns over the relationship aren't what the company at large wants, however. While Rubin's return will reassure backers worried that Essential would face a leadership crisis, it's having enough trouble getting people to buy its first smartphone -- the conduct of its founder doesn't help matters.