When moving an issue with sub-task/s to a different project, if that project is associated with an Issue Security Scheme (ISSCH), the sub-task/s will not be moved. The consequence is the parent issue belongs to the new project while its sub-task/s still belong to the original project. There are several possible variants:

1. If the original project is not associated with an ISSCH or associated with a different ISSCH (different sets of security levels):
   • If no security level is set for the parent issue in the new project, the sub-task/s will still be accessible (viewable)
     
   • If a security level is set for the parent issue in the new project, the sub-task/s will be no longer accessible
     
     
2. If the original project is associated with the same ISSCH as the destination project, the sub-task/s will be accessible and inherit the parent issue's security level but still belong to the original project
   

Expected behavior: As sub-tasks inherit their parent's security level, they should be moved with the parent to whichever projects while still inheriting the parent's security level (if available).