Where’s my refund status changed to this?

If you are receiving earned income credit or the additional child tax credit as part of your refund, the IRS is holding your refund as a fraud prevention measure as a result of a law called the PATH act.  Do not expect your refund until at least late February.

https://ttlc.intuit.com/questions/3397970-path-act-delayed-refunds-for-some-filers