I ran into this issue also, with the implicit continuation, but I couldn’t really find a viable solution. I’m considering Mockk which should support mocking suspending functions. Sorry, it’s not a very encouraging answer.
In the meantime I create my mocks manually for classes with suspending members. Generally I end up redirecting the suspending call to non-suspending functions which I actually mock, that way I still get the benefit of Mockito’s fluent syntax.