Problem of wild game found around Ulster (6)
I believe the answer is:
enigma
'problem' is the definition.
(enigma is a kind of problem)
'wild game found around ulster' is the wordplay.
'wild' is an anagram indicator.
'found around' indicates putting letters inside.
'ulster' becomes 'ni' (Northern Ireland).
'game' is an anagram of 'egma'.
'egma' going around 'ni' is 'ENIGMA'.
'of' is the link.
(Other definitions for enigma that I've seen before include "WWII cipher" , "Elgar Variations nickname" , "Mysterious person" , "Mysterious or puzzling thing" , "Puzzle found in gem, Ian" .)