Hey there, few things I just tried.
Devices on hand:
LaCIE USB-C HDD
LaCIE USB-C SSD
SanDisk USB 3.0 Flash disk (with a USB to USBC adapter)
CalDigit TB3 Mini Dock
After some testing it seems that Hot Plug is not working and TB3 isn't working although it's showing up.
A) Shutting down and Connecting BOTH USB-C HDD and SSD, turning on computer and it shows up. Ejecting and replugging doesn't work. If I eject one of them, and replug, the other one gets disconnected as well.
B) Plugging only one USB-C HDD/SSD it works on cold boot (so no hot plug).
C) Sandisk USB3>USBC adapter version of a USB flash disk does not work at all, although it seems to be getting power. This same setup works on the front USB-C panel without an issue.
D) CalDigit TB3 Mini Dock does not work at all. It says No device connected.
EDIT: Tested TB3 CalDigit Dock and it doesn't seem to show up there either?
View attachment 526658
View attachment 526659
Also attaching the SSDTs that are being used (Note am not using DTPG.aml since it's in the MCHC .aml)