Grass diet unexpectedly revised again (2-6)

I believe the answer is:

re-edited

'revised again' is the definition.

'grass diet unexpectedly' is the wordplay.
'grass' becomes 'reed' (I've seen this before).
'unexpectedly' is an anagram indicator.
'diet' with letters rearranged gives 'ited'.
'reed'+'ited'='RE-EDITED'

(Another definition for re-edited that I've seen is " changed again".)

I've seen this clue in The Independent.

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