If you go under the "Provincial" section and continue and you will make sure the last box on the bottom is unchecked "Climate Action Incentive" federal credit available for residents of Ontario" Then continue, it will not ask any questions about the CAI and it won't claim it.
If it still doesn't work, try this one out: you need to check the climate action box and then it will allow you to go through additional options and say that your wife has claimed it.
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