CREATOR GROUP and CREATOR OWNER permissions issue

I have a file permissions issue with a Netgear ReadyNAS NV+, Firmware RAIDiator 4.1.12 [1.00a043]. The NAS is used by a small company. There is no AD.

One share, which is accessible by all users, has two NTFS file permissions, in addition to the Anonymous, Group and Owner permissions. The two NTFS permissions are CREATOR OWNER and CREATOR GROUP. They are creating file access issues because when a file or folder is transferred to the share the Group permissions are not set resulting in only the owner being able to access the file. I have tried removing the two NTFS file permissions but each time this fails with no error returned. None of the other shares on the NAS have the aforementioned NTFS permissions. Could someone advise why these NTFS permissions are present and how I can remove them?

I should add that resetting the file permissions via the advanced options tab for the share enables all users to access all files within the share, but any files subsequently added have the file permission issue (and yes the NTFS permissions are still present).