Mislead party on allowance issue (13)
I believe the answer is:
consideration
'issue' is the definition.
(an issue that must be considered)
'mislead party on allowance' is the wordplay.
'mislead' becomes 'con' (I've seen this in other clues).
'party on' becomes 'side' (eg a side or party in a contract. I am not sure about the 'on' bit.).
'allowance' becomes 'ration' (I've seen this before).
'con'+'side'+'ration'='CONSIDERATION'
Can you help me to learn more?
(Other definitions for consideration that I've seen before include "factor to be borne in mind" , "Study" , "A motive" , "Bearing in mind - payment" , "Thoughtfulness - relevant factor" .)