Well, I wouldn't hold my breath on Apple giving any assistance, especially if the issue is only happening for Nvidia GPUs. They don't officially support Nvidia graphics cards (except some older Nvidia GPUs that were in some older Mac products) and Nvidia actually releases their own drivers for Mac, which has had MANY issues with High Sierra. Rumor is Apple had a falling out with Nvidia several years back, hence one of the reasons why they only support AMD cards now.
You might try contacting Nvidia instead, though I doubt it'd do much good. Rumor was Nvidia was looking to drop support for their Mac drivers with the Pascal series of cards, but a very vocal group of individuals (Hackintoshers) were able to change their mind they released their Mac Web Drivers for Pascal cards.
Personally, if it wasn't for the darn cryptocurrency mining craze and the RAM shortage, I'd of replaced my Nvidia GTX 970 with a AMD 580 by now, since I do use a Hackintosh partition on this PC. That and I'd actually like to use Wayland sessions under Linux without the terrible performance issues with the Nvidia proprietary drivers.