I recently returned from maternity leave early and my employer has decided to keep my maternity leave replacement for an additional 7 months and she will perform parts of my job duties. My position is a management position and is for one individual only. My position has not changed since I left. I was returned back to my role and same pay but I'm concerned that I'm not fully reinstated back in the role according to my ESA right because significant job duties are being given to my replacement. My employer has stated that they are allowed to make changes to roles and division of work based on operational needs. It is a non union, management role. Is this allowed and am I truly being reinstated to my role following a protective leave?

Being returned to the same job title and the same pay does not necessarily satisfy your employer's reinstatement obligation under the Employment Standards Act, 2000 (ESA). If significant duties have been stripped from your role and assigned to someone else, particularly your maternity leave replacement, that may fall short of the "true reinstatement" the law requires.
Where meaningful responsibilities, decision-making authority, or supervisory duties have been reassigned, the law may treat that as a fundamental change to your terms of employment , even if your pay has not changed. Depending on the circumstances, this could amount to a constructive dismissal, which would trigger entitlements to notice or severance. It could also engage protections under the ESA and human rights legislation if the changes are connected to your pregnancy or maternity leave.
We would need to look closely at which duties have been reassigned, the impact of those changes on the substance of your role, and whether the employer's stated justification holds up. The assessment is highly fact-specific so we encourage you to contact us to book an appointment with one of our lawyers.