SmarterMail v15.1.6005 - Bug - User Default

As System Administrator > Settings > Defaults > User Defaults > Webmail > Preview Pane

This setting is not saved when the server is rebooted. I can change the setting and it appears to stick until reboot. Following reboot, it reverts back to "Right Side".

This has been an issue since as least v12.0.5178, however because I wasn't running the current version of SmarterMail, I hadn't reported it. I just upgraded to v15.1.6005, and the issue still exists in that version.