Files have custom access after Time Machine migration to Mac mini
I recently bought a new Mini Mac (M4) Tahoe 26.6.2 and transferred files to it from an old Mac via a Time Machine Back Up. All seemed fine, but folders and basic documents such as pages and numbers files that I need to work on only have 'custom access' in the 'sharing and permissions' so short of copying and pasting everything into new documents it is all useless to me. How can I change this ?
Mac mini, macOS 10.15