hi guys just a quick one... i have keyless entry on my 525i J reg UK 1991

JUST realised that sometimes when i click the button on the key fob, instead of locking the car, it is actually locking, then unlocking in one action.

This seems only to happen when i have just closed the door! If i just stand there repeatedly pressing the button it seems ok, but why when i have just got out of the car does it do this?