Additional payments pushing back autopay on IBR plan

Hey, so I have Nelnet as my loan servicer and I keep having this issue wherein I make additionally monthly payments on my loans and then my autopay dates get pushed back. This is frustrating because it’s essentially canceling out my additional payments unless I just start consistently manually making payments and stop relying on autopay through my IBR plan. I have spoken to nelnet customer service and they basically say that I am “ahead” on my payments and it’s an automatic process that happens and they have no control over it because it’s under the governments control. Has anyone else had this issue?