Got different OSM IDs for few admin levels and the parent links are broken

I installed Nominatim two days ago and found that a few records got different OSM ids compared to the ones in the osm search. Because of that, the parent id links are broken in the installation.

For example, for OSM_ID id in OSM 63512 ( Maine state in USA) I got OSM_ID 316961875 in my installation. In fact, I don't find any record with OSM_ID 63512. Because of this, all the child nodes got impacted, they got parent_id as zero. Like this, there are 11 states got impacted and many children.

I am confused about what went wrong and not sure if it is a bug or something else I am missing.

This count shows the ones whose admin-level nodes got different OSM_IDS. All the children depending on these nodes are impacted due to this.

UPDATE - In the USA all other states are with admin_level =4 and class='boundary' and type='administrative'. But American Samoa, Maine, MD got the class as 'place' and type as 'state'