LO document on SMB share locked when users do not match

I have a FreeNAS nas running on our network with all the file sharing. All users connect to that NAS with their own credentials from a Windows 7 machine. The problem we encounter is as follows:

If user A creates a file (and thus has ownership on the NAS) and user B tries to open it, LO gives a “document is locked by unknown user” message. Both users are member of the same group and have full read-write access to that file, as they can without problem delete, move or rename the file.

How can I fix this?

Please @Bart1, try the following: Select the file with one click and wait a few seconds before double click to open.