I thought the error popped up because of the use of the reports extension but seems like it isn't the case as I am not able to replicate the issue.

Could you please try to follow our tutorial again in a new function
https://jsreport.net/learn/aws-lambda-serverless
And then test the similar calls you do

{ "renderRequest": { "template": { "name": "invoice-main" }, "options": { "reports": { "save": true } } } }

Does this also cause autocleanup errors? What do you do differently?