I keep getting Save Conflict !!!!

I'm trying to copy items from one list to another. I keep getting this error after a few items. It's completely random.

Add-PnPListItem : Save Conflict.
Your changes conflict with those made concurrently by another user. If you want your changes to be applied, click Back in your Web browser, refresh the page, and resubmit your changes.

I've added pauses and I've waited between adds. I've added waits between updates. I wait but this script don't play nice.