The problem is that the binlog position is updated before 
Executed_log_entries and Slave_SQL_State. So, it's possible to hit 
the moment when MASTER_POS_WAIT (and hence sync_with_master) already 
returned success, but Slave_SQL_State and Executed_log_entries were not 
modified yet. 
Fixing it by adding a wait on the expected Executed_log_entries value.