Without the details of your specific situation I can not explain in detail.
However, it is possible that the additional 10k of income pushed you into a higher tax bracket thus charging you more tax on your income/making lower income credits unavailable. Example going from 94k to 96k of income will cause an additional 6% tax.
Here is a quick reference link for the CRA tax brackets:
https://www.canada.ca/en/revenue-agency/services/tax/individuals/frequently-asked-questions-individu...
