If an object is moving -- a ceiling fan, plant leaves -- there are often bright blue halos around the object. Similarly, if the camera is moved before it finishes scanning, part or all of that scan may appear similarly bright blue. In rare cases, interior lighting at certain frequencies can cause blue bands as well.
Ensure everything is motionless during the scan, and make sure to wait for the OK on the Capture app before moving the camera. Where interior lighting is the problem, you may need to rely on alternative lighting sources.