Is there an external SSD enclosure compatible with OWC Aura SSD?
As far as I know, there's no such enclosure on the market today.

The reason behind the disclaimer is that the OWC drive produces more heat than the Apple-supplied drive. The enclosure simply does not cool the OWC sufficiently.

You could add some custom cooling to the enclosure (or simply not put on the lid), and make sure that the temperature stays within specs.