This is an outrage. My original budget was 50 ad credits (50usd) and it spent 100 creds. This has happened more than 5 times, meaning my original budget for all my ads were $250 and it spent $500.
My max bid was around 0.09 for all of them, and I found that once I did 0.08 or below, it wouldn’t run at all.
Assuming it’s the same issue that it was a few months ago - if you set a daily budget, but only have a duration of 1 day, then it charges for 2 days (no idea why).
I would recommend just setting life time budgets instead.