Hello there,
How are you getting to the share / folder you are accessing - are you going directly to the folder on the server, or are you browsing to it by UNC? If you are using UNC path, can you try and actually going directly to the folder through explorer and seeing if effective permissions works this way.
The below thread discusses the same issue and you can try out some troubleshooting steps from this and see if that helps you to sort the Issue.
How to evaluate effective permissions for resources on remote computers https://learn.microsoft.com/en-us/troubleshoot/windows-server/windows-security/access-checks-windows-apis-return-incorrect-results
Hope this resolves your Query !!
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