You are correct, Project Task is Task List. My fault.
I found the issue! Don't know how I'm going to get around it, but I found the issue.
I have a site column in my Project Tasks List "Assigned To" (Which I forgot to add in my post above). In the properties of the Assigned To Column, I have checked the "Allow Multiple Selections" box because more than one person may be
working the task. Unfortunatly, I can't turn the multi selection off because it is already in use.
I recreated new lists in my test environment and added a Multi Select "Assigned To" Column to the SPCascadeDropdowns child list and it show duplicates. I unchecked the "Allow Multiple Selections" and boom, no duplicates in the child listing.
If you want to recreate this bug, glitch, loophole... whatever you want to call it. Add the "Assigned To" site column with "Allow Multiple Selections" checked to your SPCascadeDropdowns child list.
Fill in the new Assigned To column with more than one persons name and then view the NewForm where you have your SPCascadeDropdowns... duplicate entries should appear in your child dropdown.
Now, all I have to do is figure out how to keep my "Multiple Selections" but remove the duplicates in the SPCascadeDropdowns child dropdown.