OneDrive for Business sharing entire drive when trying to share one specific sub folder

I spotted this bug back in June 2015 and recorded a screen capture of the steps to reproduce it.  (Here's the video: https://youtu.be/MHD7XXuDCtA)

I reproduced it today using the classic UI in OneDrive for Business, but I couldn't produce it in the modern UI.

Essentially, you select to share a file or folder and while the details pop up is open, you unselect the file -- and then click "share".  Instead of sharing a file/folder, you're sharing the entire document library.