You may have entered the donations on your wife's return and by mistake chose to split them or claim them all on your own return. I've attached a screenshot showing how this could happen.

If this is still happening after checking that it has not been claimed this way, our Customer Support team will be better able to assist you with this. Please follow the instructions below to reach an agent who can assist you with this.

https://turbotax.community.intuit.ca/replies/3152013

All of the donations were correctly entered under my spouse in the 'Receipts' page, but TurboTax still added them to my Schedule 9. The solution was to bring up the 'Charitable Donations' (DON) form. TurboTax had both myself and my spouse checked off on the form, which seemed to confuse it. Checking just my spouse fixed the issue.

That's a very odd situation for sure, glad you were able to solve it. I will take note and pass this on to our development team though. :relieved: