I had an issue with a client's conversion tracking issue where conversions stopped working for about a week...
The campaigns were all dialed in and hitting tCPA goals but when conversion tracking broke it whacked out the smart bidding.
Thankfully Google created Data Exclusions.
I created a quick YouTube video explaining how to and when to create Data Exclusions.
Hope you get some value from it and it saves you in the future one day.
To growing you ads!