Downloads stopping (not failing) at 99% was a common topic at computer help forums years ago. There were long lists of possible causes, which wasn't very helpful for most people.
I can download static images like jpg, png, bmp. Anything else abruptly fails at 95-to-99%. The file host does not matter. The built-in Tor download applet and download managers have the same problem. It's like someone turning off a switch right before the download completes.
To quote an old expression, I hope the cure is not worse than the disease.