"if you could provide a specific example where this has happened."

Where "this" what, happened, to whom? What or which "view" is this? Are you referring to my view that right now, this is a negligible amount and easily dealt with? Or, referring to my correction that this info has, in fact, been reported to the IRS?

"please explain how they could miss a married couple making Roth IRA contributions for 17 years"

I've been a plan benefits coordinator. I've seen lots of errors on the part of brokerages and managers. As a business financial consultant, I've caught banks making lots of errors, and even ADP didn't want their money back when I found their errors. I cannot explain anything 🙂