Below is the z36h (loan history) record for this transaction. As can be seen, the z36h_returned_date /_hour has been changed from the actual ("20160421 20:52") to 20160419 11:57:

{The z309 circ logger record for this transaction appears as a z309_action "24" (Return date changed).}

The only cause we know of for this is the operator use of the Override Date button in returning the item. Since the items being returned may be for the same patron, with the same need to have the returned date overridden, the default behaviour is for the Override Date button to be in effect for *multiple* transactions. As noted in article " Return date override function time out. ": "The user has to manually clear the Override button to return to the default return date."

The following SQL shows z309_action '24' instances for xxx50 on April 21 , at 8 o'clock:

Z309_DATE_X Z309_CATAL
------------ ----------
201604212001 yyyyyyyyyy
201604212002 yyyyyyyyyy
201604212002 yyyyyyyyyy
201604212002 yyyyyyyyyy
201604212002 yyyyyyyyyy
201604212002 yyyyyyyyyy
201604212041 yyyyyyyyyy
201604212052 yyyyyyyyyy <------ the return in question

We hypothesize that yyyyyyyyyy returned the item at 20:41 using the Override Date, did not hit Clear, and returned the laptop at 20:52.