After Sigma and Tamron, Tokina also issued a notice about using Tokina lenses with the new Nikon D6 camera:
Announcement on the compatibility of Tokina lenses with Nikon D6 camera
Jun 17, 2020
Thank you for Your constant support to Tokina brand.
We would like to inform You that we found functional issue with Tokina opera 50mm f/1.4 FF (Nikon F mount) when used with Nikon D6 camera (released on June 5, 2020). Other Tokina lenses work normally.
Affected model: opera 50mm F1.4 FF (Nikon F mount).
Symptoms:
When the power of the camera with the lens attached is turned ON, AF might not work properly.
After the camera recovers from “Sleep mode” AF might not work properly.
We are currently investigating the issue and will inform you as soon as possible.We sincerely apologize for any inconvenience this issue may cause.
Source: Tokina
Nikon D6 purchase links: Adorama | B&H | Amazon | WEX | Park Camera | Calumet | Camera Canada