Hi @Francis Nguyen ,
- As to your first scenario, it seems to be a known issue in SharePoint Server 2016. I could also reproduce it in my end. You can install the latest patch here to verify if the issue still persists. As an alternative, you can check items permissions via ellipsis(...) -> Advanced -> Manage Permissions.
- As to your second scenario, are you sure that those fields aren't migrated from SP2013? Generally, the migration process will not generate new fields in the lists or libraries.
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