Ok let me try and explain the nature of this change to the best of my ability and the reason why we can not change it back to the previous usage case.
Samba plays the top layer of the middleware for Linux account/access rights management. Samba does not change the actual permissions of the file/folder itself but instead maintains its own ruleset by referring to Linux permissions but not actually modifying them.
Microsoft has changed the way that CIFS/SMB authenticate and in order to work correctly we had to make modifications to our devices samba settings as well. As far as we 'know' no other vendor is offering an 'open' mode and a 'security' mode of samba working simultaneously. Generally a folder can be assigned with two access rights, R.W or RO. If a user can R/W a folder it would be strange if they also have a RO access to the folder but Samba CAN achieve this by creating a new sharename to the same path. You have seen this in our firmware by creating network permissions and a new share being created with something like Volume_1_1.
We would try 'maintaining' Linux permissions but this complicates things a bit more for both us and the user. On top of that for example if you wanted to setup permissioning for 3 users, A, B and C who belong to group "Allaccount", and whom have R/W access to Volume_1. If you wanted to say that only user C has RO access to Volume_1 that would be no problem using Linux permissions however if you have 2 accounts B, and C you wanted as RO there would be a problem because only one owner is allowed per folder. Example,
dr-xrwxrwx 6 a allaccou 4096 Nov 20 14:05 Volume_1
Believe me when I say that we are working on a viable solution to the best of our abilities but at the same time we MUST maintain proper interoperability with Windows since that is the majority market of our user base.