McCue's terms of employment had been agreed verbally over time after she began work in September 2014 and over an extended period, she raised various concerns about how time for annual and sick leave were recorded.
She and O'Boyle debated the issue through lengthy email exchanges over several days and McCue walked out of the office when things came to a head on September 25, 2018.
O'Boyle demanded she return to work and gave her a written warning for taking unauthorised leave.
McCue provided a medical certificate that stated she was experiencing work-related stress but should be able to return once issues were resolved.
McCue resigned on October 4, 2018.
In her statement of reply to the ERA, O'Boyle accepted she could have handled the situation in a more conciliatory and less emotionally-charged manner but said it had occurred during a period of significant commercial and personal stress.
ERA member Robin Arthur said McCue was disadvantaged by not having a written employment agreement and that the situation was made worse by O'Boyle's entirely incorrect assertion that while it was wise having such an agreement, it was not a statutory requirement.
"Objectively, it was foreseeable that a worker would resign rather than put up with being disadvantaged by not having a written employment agreement, being unfairly issued with a written warning and, reasonably, having lost trust that her or his leave entitlements would be correctly paid," Arthur said.
"Ignorance of these employment standards was not acceptable for any employer and far less so for Ms O'Boyle as a lawyer who could more readily than others check what was required."
Arthur ordered O'Boyle to pay $14,625 in lost remuneration, $15,000 as compensation for humiliation, loss of dignity and injury to her feelings.
She was also ordered to pay $2925 for unpaid public holidays, $675 for bereavement leave, $6750 for annual leave, and a further $4000 as penalties for failure to provide a written employment agreement.
Whangārei-based O'Boyle said she was disappointed with the ERA ruling and was considering filing an appeal with the Employment Court.