Low temperature affected Pinot? Bone of contention (4,5)
I believe the answer is:
moot point
'bone of contention' is the definition.
(thesaurus)
'low temperature affected pinot?' is the wordplay.
'low' becomes 'moo' (both can mean to make the noise of a cow).
'temperature' becomes 't' (abbreviation).
'affected' indicates anagramming the letters.
'pinot' with letters rearranged gives 'point'.
'moo'+'t'+'point'='MOOT POINT'
(Other definitions for moot point that I've seen before include "Does it need Hawk-Eye?" , "Opt motion? That remains to be debated" , "Question that may need to be discussed" .)