Rengar Ult/True Sight Cancelled by Nocturn's Ult

The title sums it up for the most part. I was recently playing a game where this came up. The enemy Nocturn ulted and I lost vision of the enemy champion in my immediate vicinity while my ult and truesight were active. Subsequently walked into a bush with 3 unintended targets that proceeded to rip me a new one.

That said, I'm not sure if this mechanic is intentional or not? True Sight usually trumps all, but any feedback or thoughts on the matter would be appreciated.

Thanks!