What area do you live in? Would help us determine what types of bunnies you have. The most common is the cottontail. Named for, well it's cotton ball like tail.That's the point - those who saw what was happening were gobsmacked! No-one's ever heard the like. That's why I offered to post in this very helpful forum which has a large membership, just in case anyone else had ever come across such a thing.
I only know about little brown wild rabbits, sorry. I've never heard of the sorts that you mention. I've googled in vain to try and find an image. We only have that sort so we just call them wild rabbits.
Beloved Bird's point about them being territorial would fit but tbh I'm also wondering if it could be a case of substance misuse.... it's not that far from a run-down area where dodgy dealings take place...suppose someone sought a secluded corner, out of town and discarded illicit stuff that eventually got absorbed into the grass?? Is that far-fetched? or might animals be affected like that?