Notice jam setting (4)
I believe the answer is:
spot
I believe this clue is a triple definition!
'notice' is the first definition.
(spot can mean to notice or observe)
'jam' is the second definition.
(I've seen this in another clue)
'setting' is the third definition.
(thesaurus)
(Other definitions for spot that I've seen before include "Pimple; place" , "Observe - place" , "20 [MARK]" , "Notice; skin blemish" , "Catch sight of mark in pots" .)