Why is this possible?

“show slave status” shows following erros state:

*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: (hidden)
Master_User: replication
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000048
Read_Master_Log_Pos: 658353090
Relay_Log_File: Ubuntu-1004-lucid-64-minimal-relay-bin.000170
Relay_Log_Pos: 5838
Relay_Master_Log_File: mysql-bin.000048
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 1062
Last_Error: Error ‘Duplicate entry ‘441569504’ for key ‘PRIMARY’’ on query. Default database: ‘serverstate’. Query: ‘INSERT INTO sensor_check (ID,SENSOR_ID,STATE_CHANGED_FLAG,RESPONSE_TIME,DATE_CREATED, CHECKPOINT_ID,SUCCESSFUL_FLAG,FAILURE_REASON) VALUES (441569504,950754863,0,607,1335713457,3,1,0)’
Skip_Counter: 1
Exec_Master_Log_Pos: 656507841
Relay_Log_Space: 2004418
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 1062
Last_SQL_Error: Error ‘Duplicate entry ‘441569504’ for key ‘PRIMARY’’ on query. Default database: ‘serverstate’. Query: ‘INSERT INTO sensor_check (ID,SENSOR_ID,STATE_CHANGED_FLAG,RESPONSE_TIME,DATE_CREATED, CHECKPOINT_ID,SUCCESSFUL_FLAG,FAILURE_REASON) VALUES (441569504,950754863,0,607,1335713457,3,1,0)’
1 row in set (0.00 sec)

…after 10 minutes without any change the “show slave status” shows folloing state:

*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: (hidden)
Master_User: replication
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000048
Read_Master_Log_Pos: 658894508
Relay_Log_File: Ubuntu-1004-lucid-64-minimal-relay-bin.000886
Relay_Log_Pos: 537737
Relay_Master_Log_File: mysql-bin.000048
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 658894508
Relay_Log_Space: 537915
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.00 sec)

who is it possible?