"The Climate action incentive payment (CAIP) is a quarterly payment. The first CAIP payment you received in July 2022 included the first two payments in the year combined, meaning April and July 2022. Your subsequent CAIP payments for October 2022 and January 2023 will be lower as they do not include a retroactive payment such as July."
https://www.canada.ca/en/revenue-agency/services/child-family-benefits/cai-payment.html