A lot of rabbit references both in the faction challenges (they're different for each faction. Each one refers to a rabbit) and the weekly quest (Down the rabbit hole).
→ unfortunately no real hints in the chapters of the weekly quest
Definitely something with rabbits and 100% an april fools joke.
There's one on the Harbor map, too. I threw a bomb at it, but it didn't do anything. Would be cool if you could shoot it and get an exclusive outfit or ornament or something. Maybe a weapon set...