When in standard, Mac-driven file selection dialog windows (e.g. Create New, Open, Import Audio, etc.) using keyboard-based navigation (e.g. Left Arrow, Right Arrow, Cmd+Up, Cmd+Down, etc.) too rapidly causes the entire app to freeze for several seconds, then crash completely, presenting the standard 'Send to Avid' option.
This is not only frustrating, but also a great way to lose work!
Known to occur in Pro Tools 12.7.1, running on macOS 10.12. Unknown if impacting other versions.