Aquantia is to blame. The latest driver on ASUS website for XG-C100C is dated around April 2017. That is almost 10 months without any driver update.
10 month without update? That's nothing for a driver and provided there is no new hardware to support, no significant change in the driver interface or in OS power management, there is no need to update a properly written driver for years.
It may not be Apple's fault completely beause Apple expects only iMac Pro hardware on their macOS. They don't care about any other possible scenario and totally not concerned about Hackintosh users.
That's what the military calls collateral damage and as Macs also support Windows 10 there are several supported scenarios in which this kind of damage may occur (a Aquantia card in a TB to PCIe expansion case attached to a Mac running Win 10 and High Sierra).