Items are disappearing from locker when plugin is reloaded

Hi there! 

There have been a number of players reporting that their items are being deleted from their portable lockers. 
I logged in to test and initially, nothing happened. My items remained in the  locker. 
It wasnt until I was adjusting the permissions and reloading the plugin that the items disappeared. 

So I set the "items persist after wipe" setting to true,  reloaded the plugin, put items in the locker - waited a bit, and then reloaded the plugin again. 
Again.. All items were lost. 

How do I set it so that items arent being deleted ?? 

Thanks!