Please take a look at the bidding settings for your campaign(s).
You can set a MAX CPC but if you have enabled Enhanced CPC - Google will automatically adjust your MAX CPC.
"Enhanced CPC will dynamically adjust your Max. CPC bid up or down for each auction in an effort to acquire more conversions while maintaining your current CPA. As a result, a given click could cost up to 30% more than your bid. Learn more."
Hope this Helps!
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