Symptoms

In current versions of K2 (4.7 included) Hyperlink control always converts URL to lower-case. In most of the cases this does not cause any problems but sometimes it does. For example Salesforce uses case sensitive URLs and converting its URLs to lower case breaks them.
 

Diagnoses

This is known issue (internal ID 712185) which bound to be addressed in the future versions of K2.
 

Resolution

This is known issue (internal ID 712185) which bound to be addressed in the future versions of K2. You may use alternative ways of presenting hyperlinks to workaround this issue.