rek sai bug?

I have recently played a game and i found out that i could could see rek'sais tremor sense but i was playing as akali. Is this a bug? I forgot to say that rek'sai was on my team. There was an enemy azir and I couldn't see him but due to the tremor sense from reksai I could track him down and get the kill. If this was intended, it is certainly very weird and if it wasn't, that makes total sense because rek'sai is a very new champion and still needs improvement. If you can help please comment on this.