UserAgent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:50.0) Gecko/20100101 Firefox/50.0

Steps to reproduce the problem:
1. Connect a Wii U USB GameCube Adapter to the computer.
2. Connect a GameCube controller in the adapter's port 1.
3. Download Wii U USB GameCube Driver. If required, download as well Zading and vJoy.
4. Install Wii U USB GameCube Driver.
    a. When Zadig is prompted, replace original driver with WinUSB.
    b. When vJoy is promopted, follow vJoy's installation process with the default configuration. If vJoy installs succesfully, skip to step 5.
    c. If vJoy installation fails, run vJoy independent installer again.
    d. If the failure persists, delete folder %userprofile%/usb_driver and run the installer again. Repeat d. until installation succeeds.
5. Run Wii U USB GameCube Driver/adapter. When prompted, press Start.
6. Run Chromium or Chrome dev channel, and go to http://html5gamepad.com/
7. Press any of the GameCube controller buttons.
If the first device detected in the gamepad list is the one that is reading input, do the following:
8. Reset cache and refresh the page. If the result persists, continue through step 9.
9. On the Gamecube USB Adapter Driver window, press the Windows Gamepad Info.
10. On the prompted window, check "Disable ports on exit", and close the program. A DEP window should prompt noting that the application has stopped working.
12. Repeat from step 4.
13. Reboot the computer if the bug couldn't be replicated when reached this point, then repeat from step 4.

What is the expected behavior?
The ports should be assigned in accordance to their respective ports: The first detected gamepad device should be the one connected on port 1, the second being the one on port 2, and so on.
This expected outcome has been reported on Firefox 50 100% of the time.

What went wrong?
Three buggy outcomes have been reported:
1. Mismatched order of devices (i.e. Gamepad connected on port 1 being the last gamepad device listed on navigator.getGamepads();)
2. All gamepads detected are 'undefined'.
3. One of the gamepads, completely unresponsive, has the id set to "Unidentified Device (Vendor: 0000 Product: 0000)", instead of the "vJoy - Virtual Joystick (Vendor: 1234 Product: bead)" expected id.

Did this work before? N/A 

Does this work in other browsers? Yes

Chrome version: 56.0.2924.3 (Build oficial) dev (64 bits)  Channel: dev
OS Version: 10.0
Flash Version: Shockwave Flash 23.0 r0

It may be necessary to repeat some steps in order to replicate this bug.