same problem happended again
sent a Bug report here : https://jira.secondlife.com/browse/VWR-27664
I went "Le Tigre" server it doesnt fix.
Clear Cache wont work.
In this article fixed by relog which doesnt workd for me http://community.secondlife.com/t5/Inventory/Why-am-i-getting-system-folders-when-some-one-passes-me-a-folder/qaq-p/1029643 http://community.secondlife.com/t5/Inventory/how-can-a-normal-folder-turns-into-system-folder/qaq-p/1030481
inventory maintenance didnt fix it, so i think it is bug.