I don't see too much resemblance myself and there was no conscious effort of mimicking their design but a lot of project management apps do look fairly similar, UX wise.
Maybe it's just that I use LH daily, and that bug trackers and project management apps have only so many possible options for UX - but to me, these two look more alike than any other combinations I can think of. Not implying it's a rip off - it just struck me as funny.