Why is my personal Ipad now asking for remote management credentials

Was this iPad purchased used perhaps?

Remote Management indicates that the device once belonged to an organization utilizing Apple Business/School Manager and Mobile Device Management. There is no way around this other than to contact the organization that is managing the device.

If you purchased the device directly from the org, then it is possible that someone did not completely release it before handing it off. If you purchased the device from an individual, the org likely did not release the device and may ask for it to be returned.

The All Too Common SAD Reality of Buying a Used iPad/iPhone - Apple Community

Did you have it repaired through a 3rd party vendor…. Like Squaretrade or Allstate or asurion. You know one of the companies that offer insurance through Walmart or target? Because I just had the same problem and I bought mine new. But sent it in for repair and they repaired the mother board in mine and all this time I’ve never factory reset it until today…. And found out the serial number outside doesn’t match the inside… so the repair company used someone’s old parts to “fix” my tablet…. And now the Detroit public school system wasn’t remote management to my iPad…..