Just as I was about to post this on audacityteam.org, I figured I should try here, first. If this has been mentioned here before, I apologize but, since it's not in Known Issues...
I'll be playing a track in Audacity and suddenly, after I do something — not sure but I think I pressed the spacebar to stop — sound stops, the cursor keeps on going as if it's still playing, and the application won't respond to the mouse, keyboard or anything. This continues until the cursor reaches the end of the track. Then, everything returns to normal.
I'm unable to reproduce it but I've seen it happen two or three times since installing a few months ago.
OS: Windows 10 Enterprise 64-bit
Install path: H:\PortableApps\AudacityPortable (new installation)