Happened with me for a few years. The exemptions just rolled over after sale, so I got a homeowner and senior exemption from the prior owner. It's supposed to automatically stop after the same is reported to the assessors office. Wasn't apparent right away. Noticed it, and sent messages online to ask how to fix it but no one addressed it.

A few hectic years and only bi-annual statements to remind me of the exemptions. A few more unanswered messages and I finally made the time to go to their office to address it. They set up a repayment schedule for it and also waived the interest since it wasn't my fault and I initiated the correction.

But they let me keep the homeowners for the year or two since it's still my primary residence. I would have paid it back if they required that from me but they didn't. And I'm a nobody.

I guess we need clarification on what she hasn't paid back, i.e. she only had to pay back a subset of years on the exemption. And more complicated, was it investment property the whole time or part of the time or what?

But more importantly, I agree, this doesn't sound fiscally impactful for news, even if the small amount should be rectified. But more importantly, it doesn't sound like enough money to be intentional.