Not forthcoming about page in issue (4)
I believe the answer is:
copy
'issue' is the definition.
(thesaurus)
'not forthcoming about page' is the wordplay.
'not forthcoming' becomes 'coy' (I've seen this before).
'about' means one lot of letters goes inside another.
'page' becomes 'p'.
'coy' enclosing 'p' is 'COPY'.
'in' is the link.
(Other definitions for copy that I've seen before include "Emulate, ape" , "what's to be printed" , "Duplicate" , "Text for an article" , "The editor wants this" .)