Executive Summary: Key Legal and Evidentiary Issues

• Centre de services scolaire de Sorel-Tracy applied for judicial review of an arbitral award ordering it to pay salary insurance benefits to a teacher for the period of 23 August 2023 to February 2024.
• At issue was whether the teacher qualified as invalid under the collective agreement while working a partial schedule due to a new and unrelated psychological condition — conversion disorder.
• Two collective agreement provisions were in conflict: clause 5-10.03, defining total disability, and clause 5-10.27(B), governing progressive return to work contingent on continuity of the same pathology.
• Medical evidence confirmed the teacher's original condition — dissection of the left vertebral artery — was consolidated by January 2023, and that she could only permanently perform 66% of her regular duties.
• Reasonableness was the applicable standard of review under Vavilov, requiring the arbitral decision to be internally coherent and justified in light of relevant legal and factual constraints.
• Contradictions within the arbitral award were fatal: the arbitrator simultaneously found the new condition unrelated to the original dissection, then concluded it derived from that same dissection.

Facts of the case

A teacher employed by the Centre de services scolaire de Sorel-Tracy suffered a first period of disability due to a dissection of the left vertebral artery, spanning from February 2022 to April 2023. The employer's expert physician declared the pathology consolidated in April 2023, a finding the teacher's own treating physician did not dispute, having reached the same conclusion as early as January 2023. When the 2023 school year commenced, the teacher was unable to perform her full duties and took on only two student groups instead of the three her position required. She claimed salary insurance benefits to cover the difference between her actual wages and her full salary. The employer refused, on the basis that her condition was no longer connected to the originally recognized disability and that the progressive return provisions of the collective agreement therefore could not apply.

Contractual clauses at issue

Two provisions of the collective agreement were central to the dispute. Clause 5-10.03 defines disability as a state of incapacity resulting from illness or accident that renders a teacher "totally incapable of accomplishing the usual duties of their employment or any analogous employment offered by the school board at similar remuneration." Clause 5-10.27(B) governs progressive return to work: it permits a school board and a teacher who has been absent for at least 12 weeks to agree on a phased return, during which the ongoing period of disability continues without extending the maximum 104-week benefit period. Under that provision, the teacher receives salary for the proportion of duties performed and salary insurance benefits for the proportion not performed. Critically, the clause contemplates a return that is a continuation of the same period of disability — not the onset of an entirely new and unrelated condition.

Reasoning and analysis

The Superior Court applied the reasonableness standard set out by the Supreme Court of Canada in Vavilov, under which a decision must be both internally coherent and justified in light of the applicable legal and factual constraints. The court noted that the arbitrator's analysis contained irreconcilable findings. At paragraph 97 of the arbitral award, the arbitrator acknowledged that the teacher's symptoms at the start of the 2023 school year could not be linked to her 2022 dissection, which had resolved by January 2023 according to her own physician. Yet at paragraph 114, he concluded that the new disability "derived from the dissection" and was not attributable to a condition completely unrelated to the prior invalidating cause. At paragraph 121, he reverted to finding that the teacher was invalid "not because of her dissection, but because of a new illness that had developed over time, namely conversion disorder." The court found these statements flatly contradictory and incompatible with any coherent application of the collective agreement. The court further reasoned that the agreement left only two available scenarios: either the teacher was fully unable to work and therefore entitled to full salary insurance benefits under clause 5-10.03, or she was on a progressive return under clause 5-10.27(B) as a continuation of the same pathology — tertium non datur. The arbitrator's approach of combining both regimes to accommodate a new and unrelated condition had no basis in the text of the agreement, and no collective agreement provision was cited to authorize salary insurance payments to a teacher working part-time due to a permanent partial incapacity arising from a new condition.

Ruling and overall outcome

The Superior Court allowed the application for judicial review, quashed the arbitral award rendered by Me Gilles Ferland on 21 March 2025, and referred the matter to a new arbitrator to rule on grievance no. 2023-0001896-5110 filed on 21 September 2023. Costs were awarded against the respondent. The successful party was the Centre de services scolaire de Sorel-Tracy. No specific monetary amount was ordered in favour of the employer; the court's relief was procedural in nature — annulment and referral to a new arbitrator — rather than a damages or compensation award.