Firstly, the object design for your solution is incorrect. 7continentslist and wikipedia are different browser applications, you should not have a single object for both of these, you should have different objects for them. This will solve your issue, as you will not be using Navigate URL. You should have an experienced Blue Prism user or consultant available to you to evaluate your object designs.
If you do need to use Navigate URL (to naviage to different pages within the same application rather than navigating to totally different applications) there is a known issue in version 5 of the product that stops Navigate URL from working. It is currently being worked on by the product team so a fix shoudl be expected in a release shortly.
In the meantime your workaround is to navigate between screens in your single application as you would manually (clicking on buttons/menu options etc) rather than using navigate url,