He resentenced Cottle to eight months' home detention and 200 hours' community work.
But it came with a caveat.
''There's something about this case which troubles me immensely,'' Justice Davidson said.
He ruled that Cottle should come back before him in three months so he could ensure the man's issues were being appropriately addressed.
On July 6 last year, the defendant was driving his ute in Kaikorai Valley Rd when he saw another vehicle driven by a man he believed owed him $400.
He drove at the victim, causing him to take evasive action, then followed the man along the motorway.
When the victim stopped in Mosgiel, he rammed the Toyota Hilux three times.
Four months later, Cottle became enraged again.
Driving through central Dunedin, he noticed his ex-partner with another man while stopped at a red light.
He immediately rammed the car from behind, reversed and shunted them again.
Cottle then lay in wait outside his ex-girlfriend's Green Island home until she was dropped off.
He approached the car with an axe and tried to open the driver's door.
''When the door would not open, the defendant raised the axe up above his head and swung it, using the cutting edge of the axe to smash through the driver's side window where [the victim] was sitting,'' the police summary said.
''This seems to me to be right on the edge of something that could be extremely serious,'' Justice Davidson said.
Cottle dropped the axe and inflicted more than a dozen blows on the victim.
When his ex-partner removed the weapon from the scene, he produced a knife and slashed the valve on the Mitsubishi's tyre.
He was arrested days later, after a manhunt in Central Otago which involved 35 police staff from around the region, as well as a helicopter, dog units and a drone.
Cottle was picked up from the Otago Corrections Facility by his parents yesterday, the court heard, and will serve his sentence of home detention in Mosgiel.
Justice Davidson said he hoped the man had received treatment for his impulsivity when he saw him in three months.
