You could try removing the EPM-auto-assign handler from the 'Designer Acknowledgment' task as you have EPM-auto-assign-rest on the root of the workflow. From the documentation:
"If this handler is attached to the root task with no argument specified, the workflow process initiator is made the responsible party for all tasks in the workflow process."
It might be confusing it?
Also, you have 2 routes going to the "Check & Review" task. You never used to be able to do this, you always had to use an 'Or' task. Not sure if you are able to do this now... I still always put 'Or's in my workflows to collect multiple paths.