Using the AWS Solution Kit 1.0.01 to allow the API Gateway to directly invoke AWS Lambda functions and it was noticed that
when invoking a high volume of calls in a short time frame the data received on the lambda side can be incorrect in some instances. It appears the data received in those cases is from a previous request.
This situation has been addressed in the latest AWS Solution Kit.
Please open up a support issue and request AWS Solution Kit 1.0.03 or later.
You can then upgrade the current AWS Solution Kit via policy manager->tasks->Extensions and add-ons->Manage Solution Kits
Choose the current installed AWS Solution Kit and then the upgrade button. Choose the skar file associated with the new AWS Solution Kit 1.0.03
Once you go through the steps to upgrade the AWS solution kit then restart the gateway service. Upon testing you should no longer see the concurrency issues being experienced previously.