The incident occurred in Auckland on July 15, 2021.
The IPCA said police were "unjustified" for removing the charges and described the decision as "inexplicable".
The IPCA report said the officer was not justified to taser a man in a police holding cell.
The offender had tried to steal a motor-scooter on Auckland's Karangahape Road in May last year.
Fraud and deception are among the most common offence types.
The dog handler was on his own and facing an offender intent on assaulting him.
The IPCA said there are unclear expectations on supervisors while off-duty which puts the police's reputation at risk.
The son was charged with assault after punching a woman outside a popular bar in Whangārei.
The IPCA said the officer's actions "posed a significant risk of serious harm to the man".
