AWS event triggers conflict sometimes

We’ve had this problem before where there’s a conflict for event triggers of S3 and SQS and CloudFormation (CF) throws an error and rolls back:

The following resource(s) failed to update: 

The odd one out here is CheckoutAuthLambdaPermissionApiGateway which is a Authorization Lambda in API GW…

We have three different AWS acconts (Test, QA and Production) and this has happened from time to time in all environments.

AWS CF then rolls back to a previously know working state. If we remove all the events from AWS manually and re-deploy it works fine again.

Why does this keep happening?

Did a bunch of testing and managed to recreate the issue in our Test environment…

CloudFormation - CREATE_FAILED - AWS::S3::Bucket - S3BucketQvaliafilestoreqabgfilesservice

The issue is that CF errors on already exists

However this CF Stack has existed since 2018 and haven’t caused issues before…

Why would it start complaining about a Bucket (well, two buckets actually) all of a sudden…?

Bucket creation date is August 29, 2018, 10:45:38 (UTC+02:00)