Upset on account of shift (8)

I believe the answer is:

overturn

'upset' is the definition.
(I know that upset can be written as overturn)

'on account of shift' is the wordplay.
'on account of' becomes 'over'.
'shift' becomes 'turn' (turn is a kind of shift).
'over'+'turn'='OVERTURN'

(Other definitions for overturn that I've seen before include "Capsize - invalidate" , "Reverse (decision)" , "tip" , "Invalidate - upset" , "Crash" .)

I've seen this clue in The Times.

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