Thank you for using our services.
The behavior that you are describing may come from the fact that your user controls have PostBack Url set in them. This causes Sitefinity pages and templates to "freeze" and behave as described. You can look at Sitefinity page freezes in Edit mode
KB article for more information.
One more thing. Sitefinity Standard Edition supports versioning of pages and templates (see attached image). That means that when a problem like this occurs you can roll back to a working version of the page/template. Please note that this is not available in Community Edition.
if you have more questions, please feel free to contact us.
the Telerik team