Good Morning,
I was unaware of the processing times, and applied for a renewal on May 4, 2018. I spoke with a Nexus person yesterday, who advised that 10-12 weeks for renewal is the norm. According to the person I spoke to from the Vancouver office, the US processed their portion on May 8, 2018, and the rest of the time was the Canadian portion.

It was confirmed that use of the card after the expiry date is permissible, but that one should have a copy of their payment receipt and printout of the screenshot showing the renewal has been applied for.

Coincidentally, I received notification of my approval today...