We have seen issues with using four or more Nested Groups, working in Camtasia Mac.
What is a Nested Group?
A Nested Group is a group that has been placed inside or that was created in an existing group.
For more information about groups please see the following link here
Currently the largest amount of groups we recommend nesting is four (this would be for placing groups inside of groups; this is not a limitation of total groups used in a project).