According to the FreeNAS forum the update to 9.10.2-U2 might have caused issues with the SMB permissions.
You could try adding the following to the Admin Menu > Edit configuration file (for experts) in
SECTION fileserver
...
CIFS_MOUNT_OPTION=sec=ntlm
...
ENDSECTION fileserver
a network trace would give us more information about the negotiation between camera and file server and the options enabled on the server side. It might be easier to get the CIFS configuration file instead.
With the level of segmentation, due to the different versions and customization options available in CIFS and the different MOBOTIX camera models and software lines we would need more details to determine if there is a common problem.