GPT "protective" partition? & USB 3 dock vs SATA direct

I hope I'm remembering the details here correctly.

I have a 3TB WD WD30EZRX disk that I want to use under Linux and Windows 10 through a Sharkoon Quickport XT USB 3.0 dock, but the contents on several NTSF partitions were unreachable on two different Windows 10 systems, and the drive showed as containing 16384 GB under a single "GPT protective partition".

Yet when plugged it into an SATA port on one of those Windows 10 systems, the contents were visible. I backed them up on another drive.

Then I booted a gparted live image, where I reinitialized the disk and created a new GPT single partition. Again using the dock it was unreadable identically on the Windows systems.

Under Windows I used DISKPART to reinitialize the disk as GPT and create a single partition. Now the contents of the disk are correctly visible, using the dock, on both systems.

Question 1: once initialized using Windows DISKPART, the disk is usable through the dock on both systems. Why through DISKPART and not through gparted?

Question 2: why was the disk originally readable with a direct SATA connection but not using the dock? Any idea?