Dear Hannah,
Good day. Thank you for reaching out.
I understand that you are having an issue where the due date in tasks changes to the day before. May I please verify if this is the same case when you use To-Do on the web?
If that is the case, we have received a number of requests on this from different users about the same issue and changing the Tasks view from Grid to List seems to show the correct date. Please confirm if this is the same case on your end.
If the issue persists, I'd recommend reaching out to the To-Do community directly. You can do so by posting via Microsoft To Do Community, so that a support agent from this team can check and provide you required information. At this moment, your kind cooperation and understanding will be highly appreciated.
Thank you so much for your precious time. Stay safe and healthy.
Best Regards,
Ashraf.