Like problematic jar of marmalade? End up with one chucked! (8)
I believe the answer is:
unopened
'like problematic jar of marmalade?' is the definition.
(a jar needs to be opened)
'end up with one chucked' is the wordplay.
'with' means one lot of letters go next to another.
'chucked' indicates an anagram (letters chucked around).
'end'+'up'+'one'='endupone'
'endupone' with letters rearranged gives 'UNOPENED'.
(Other definitions for unopened that I've seen before include "Still closed" , "shut" , "barred" , "Still sealed as post may be" , "Remaining closed" .)