Thanks, I see the issue, appreciate you taking the time to notify us.
For now you can select the following cluster:
spine_5_clusterHandle
and set the parent constraint's interp type to 'shortest'
The name of the constraint is: spine_5_clusterHandle_parentConstraint1 if you'd like to select it directly
Might want to do the same for spine_6_clusterHandle to be safe.
Let me know if you have further issues
Andy