Happens to apply for release (5)

I believe the answer is:

issue

'for release' is the definition.
(synonyms)

'happens to apply' is the wordplay.
'happens' becomes 'is' (to be can mean to happen).
'to apply' becomes 'sue' (I've seen this before).
'is'+'sue'='ISSUE'

(Other definitions for issue that I've seen before include "Important topic for debate" , "Publish, bring out" , "Offspring; publish" , "Matter, point" , "Topic (to be addressed)" .)

I've seen this clue in The Times.

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