Embarrass person of substance when lot includes forgery (3,5)

I believe the answer is:

fat shame

'embarrass person of substance' is the definition.
(as in fat shaming an overweight person)

'lot includes forgery' is the wordplay.
'lot' becomes 'fate' (synonyms).
'includes' is an insertion indicator.
'forgery' becomes 'sham' (sham is a kind of forgery).
'fate' placed around 'sham' is 'FAT SHAME'.

'when' acts as a link.

I've seen this clue in The Guardian.

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