Unable to rename subfolders on Unity

Hi

We have a share on a File system where we are unable to rename or cut and paste folders with files in them.  Even with full permissions to the folders and files.  If the folders have files in them a rename or cut and paste get denied.  If we go in we can delete the files and then the folder can be renamed or deleted without any issue. 

The File System has FLR-E enabled on it but it's not had any rules set on any of the folders so none of the files are locked.  I thought this was possibly the culprit as we have another File system without FLR that has no issue.  After a bit of a google I found this relating to VNX  - https://www.dell.com/support/kbdoc/en-uk/000052134/can-t-rename-a-non-empty-directory-on-a-flr-enabled-fs  but from the documentation on FLR on the Unity it seems to suggest it should all be OK without any locks set.

Can anyone advise or have experience of this at all?

Thanks in advance

Mr_B