Mortgage being sold, current lender is telling us we need to refinance
I've had my mortgage for a few years and it had been sold to someone else a year or so back, then returned to the original bank, and now it's being sold again. We've been serviced through the original lender the entire time and will continue to be serviced through this lender so we've been using the same portal and account and everything.
Our servicer told us that the new buyer is requiring us to refinance so the servicer said they can offer us a slightly lower rate and there won't be any costs for us. Our servicer is a relatively small bank, the new lender is Fannie Mae. We can either get a new 30 year mortgage or honor our current remaining time.
I've never heard of needing to refinance because the mortgage was sold and I don't understand why they would offer us lower terms. It seems too good to be true even though it's a very small rate decrease. I'm going to call the servicer about this but what am I missing? Has anyone been through this before?