range rover vogue air suspension problem ?

hi i was flashed and stopped today by a driver who said my range rover 2003 4.4 vogue the driver side rear shocker/air suspension was jumping like mad while the rear passenger side was ok, will it be the rear air spring/air bag gone ? any ideas please steve every time i use this car i get another fault !! how much fun can you have

You were driving and didn't feel/notice it