Finally heard back from someone at Fyber (formerly Sponsorpay) regarding their intention to update their Corona plugin.
we don’t have any plans to update Corona plug-in yet based on the overall market demand for it, however depending how developer interests changes, we will accordingly shift focus on Corona.
I suspect the current plugin is quite old and for an older version of their SDK, so it’s probably not in compliance with Google’s new Ad Identifier requirements. Use at your own risk.