1. You can try restarting VS and rebuilding the project.
2. If it persists, please reset all your debug-related options (Tools -> Import and Export settings -> Reset all settings ->No, just reset...).
3. If it not works, go Tools -> Options -> Debugging -> General to check both "Use the legacy C# and VB expression evaluators" and "Use Managed Compatibility Mode".
4. Delete the hidden .vs folder in my project folder.
	(Once I deleted it, reopen the project, and DataTip returns back to normal.)