While her appeal against two breaches and a burglary conviction were dismissed, the judge allowed her appeal against sentence, and shortened her two-year, nine-month prison term.
The latest convictions relate to earlier this year, while the victims were overseas on a holiday.
Mitchell was spotted on CCTV entering their backyard late at night and trying door handles at the rear entrance to the house.
She denied trying the door handles and said she was just there to visit the cats.
Mitchell did not know there were houses sitters who called police. Mitchell fled the scene and was found crouching in another house's front yard.
Previous offending includes sending the stick figure illustration, numerous letters from prison, and visiting the victim's home about 11.30 one night, armed with a tyre iron, smashing most of the accessible windows in his house.
In a decision released today, Justice Francis Cooke said Mitchell had a brief relationship with the victim which ended in the mid 2000s.
"Since then she has had an unhealthy fixation on the victim and his wife. A protection order had initially been obtained on 24 April 2008, and in May 2010 was extended to protect the victim's partner," Justice Cooke said.
"Ms Mitchell has continued to harass the victims despite the imposition of the protection orders. She has served several sentences of imprisonment for offending against them and has amassed a large number of convictions."
He dismissed her appeal against the convictions, but found the sentencing judge had given her too long a jail term.
He said the sentence should not have been longer than the one imposed for the window-smashing incident in 2013.
Justice Cooke quashed Mitchell's sentence and replaced it with one of 18 months imprisonment.
He also imposed release conditions that included an order that Mitchell not travel south of Levin and Eketahuna for six months after her release.
