Exporting fabrication files (gerber) in Altium leads to wrong connections
When you view the files in Camtastic, you are already viewing the Gerber files.  Camtastic is a "Gerber File Viewer and Editor".

You do not need to export anything from Camtastic.  

After you generate the Gerber files (typically done using an 'OutJob' file), simply open the output folder in your project files (using windows explorer), and zip up the output files you need to send to your pcb manufacturer.

You can use Camtastic to view the generated Gerber files, and pseudo-independently confirm that they are ok and conform to some rules (see the Camtastic analysis menu).  

Sometimes, in rare and advanced circumstances, one would want to edit Gerber data using Camtastic, and re-export using the tools in Camtastic program.  However, this is really unusual now-a-days, and I have not had the need in a decade.

Camtastic can be used as part of the process to reverse engineer Gerber data back to a pcb file.  But this also is an advanced and unusual requirement.

'OutJobs' are your friends.  You'll be happier if you use them.