i found error log that make no sense after DB sync on AX 2012 R2 CU7. the table that the error pointed to already deleted, but the error still occurred.
here is the solution :
“If you are getting synchronization errors that do no make sense or that you think you should have already resolved there may be old records left in the SQLsyncinfo table or have old or incorrect object ID references. If you suspect this make a database backup, shutdown the AOS, in SQL run truncate table SQLSYNCINFO, start the AOS and run a new Synchronize from the AOT.”