Ejecting a USB 3.0 drive connected to USB 3.0 port reconnects immediately

I have an external HDD with a USB 3.0 connection. When I connect it to the USB 3.0 port on my laptop, it works fine but when I eject it, it gets remounted immediately.

This doesn't happen when I connect the same drive to a USB 2.0 port.

At the moment I'm unmounting (clicking the "eject" button in Nautilus) instead.

Is there a way to avoid this issue?

I've found 3 workarounds:

1. attached to bug https://bugs.launchpad.net/ubuntu/+source/nautilus/+bug/792085 there is an advice to uncheck "Mount removable drives when hot-plugged" setting: https://launchpadlibrarian.net/191200111/Thunar_uncheck_setting.png
2. edit the BIOS settings: a) set xHCI mode to manual and b) disable the "xHCI pre-boot driver". It seems to solve the problem and supposedly leaves the USB 3.0 mode switched on. I've applied this method but, sorry, haven't tested it thoroughly yet.
3. a hard and violent workaround: just disable USB 3.0 mode in the BIOS settings - disable the xHCI interface, which is essential to USB 3.0. It helps... Although slows down the USB...