Faultily execute right about turn (3)

I believe the answer is:

err

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'faultily execute' is the definition.
I can't judge whether this definition defines the answer.

'right about turn' is the wordplay.
'right' becomes 'r' (common abbreviation).
'about' becomes 're' ('re' means regarding or about).
'turn' says the letters should be written in reverse.
'r'+'re'='rre'
'rre' back-to-front is 'ERR'.

Can you help me to learn more?

(Other definitions for err that I've seen before include "Go astray" , "Make a wrong move" , "Make mistake in Canberra" , "Blunder" , "Boob" .)

I've seen this clue in The Globe and Mail.

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