Posting Periods Unlocked Automatically

Dear Experts,

Currently, we are having problems in the posting periods in SBO. The posting periods will be unlocked automatically while the users never login to change the posting periods. Is there any bugs in SAP B1 8.82 PL12? This has been happened for few times already. I have checked the change log and it showed that 2 user IDs - acstaff & itadmin have changed the posting periods while the users did not change the posting period. I am using itadmin to login to SAP and I never change the posting period but it showed Updated 24/02/2015, Updated by itadmin when I clicked on the change log of posting period.

Kindly guide me on the above issue.

Thanks & BR,

Leng