Substitute in court causing trouble (6,2)

I believe the answer is:

acting up

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'causing trouble' is the definition.
I can't judge whether this definition defines the answer.

'substitute in court' is the wordplay.
'substitute' becomes 'acting' (e.g. acting president).
'in court' becomes 'up' (up before a judge).
'acting'+'up'='ACTING UP'

Can you help me to learn more?

(Other definitions for acting up that I've seen before include "Misbehaving" , "Behaving badly" .)

I've seen this clue in The Times.

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