Has the same been observed in spot-on treatments?

I treat my cat with imidacloprid, as it is bunny safe and I don't want my rabbit potentially being harmed by being in close proximity to the cat. It looks like imidacloprid is one of the active ingredients in this collar, however.

So far I've not observed any adverse effects in either animal, but this does concern me a lot. Bizarrely, I take care of their health more than I do my own...