Caught copper cutting joint - it's a minor setback (6)
I believe the answer is:
hiccup
'a minor setback' is the definition.
(I've seen this before)
'caught copper cutting joint' is the wordplay.
'caught' becomes 'c' (cricket abbreviation).
'copper' becomes 'cu' (chemical symbol).
'cutting' indicates putting letters inside (some letters cut their way into a word).
'joint' becomes 'hip' (hip is a kind of joint**).
'c'+'cu'='ccu'
'ccu' put within 'hip' is 'HICCUP'.
'it's' is the link.
(Other definitions for hiccup that I've seen before include "minor issue" , "Temporary setback (colloq.)" , "Sudden throat sound or minor mishap" , "Minor problem" , "Involuntary spasm of the diaphragm" .)