AppSync request mapping template errors not logged in CloudWatch - amazon-cloudwatch

Question

Crosspost from: https://repost.aws/questions/QUp5jDZ6bsRkeXhIwHgQaWkg/app-sync-request-mapping-template-errors-not-logged-in-cloud-watch
I have a simple resolver that has a simple Lambda function as a data source. This function always throws an error (to test out logging).
The resolver has request mapping template enabled and it is configured as follows:
$util.error("request mapping error 1")
The API has logging configured to be as verbose as possible yet I cannot see this request mapping error 1 from my CloudWatch logs in RequestMapping log type:
{
"logType": "RequestMapping",
"path": [
"singlePost"
],
"fieldName": "singlePost",
"resolverArn": "xxx",
"requestId": "bab942c6-9ae7-4771-ba45-7911afd262ac",
"context": {
"arguments": {
"id": "123"
},
"stash": {},
"outErrors": []
},
"fieldInError": false,
"errors": [],
"parentType": "Query",
"graphQLAPIId": "xxx"
}
The error is not completely lost because I can see this error in the query response:
{
"data": {
"singlePost": null
},
"errors": [
{
"path": [
"singlePost"
],
"data": null,
"errorType": null,
"errorInfo": null,
"locations": [
{
"line": 2,
"column": 3,
"sourceName": null
}
],
"message": "request mapping error 1"
}
]
}
When I add $util.appendError("append request mapping error 1") to the request mapping template so it looks like this:
$util.appendError("append request mapping error 1")
$util.error("request mapping error 1")
Then the appended error appears in the RequestMapping log type but the errors array is still empty:
{
"logType": "RequestMapping",
"path": [
"singlePost"
],
"fieldName": "singlePost",
"resolverArn": "xxx",
"requestId": "f8eecff9-b211-44b7-8753-6cc6e269c938",
"context": {
"arguments": {
"id": "123"
},
"stash": {},
"outErrors": [
{
"message": "append request mapping error 1"
}
]
},
"fieldInError": false,
"errors": [],
"parentType": "Query",
"graphQLAPIId": "xxx"
}
When I do the same thing with response mapping template then everything works as expected (errors array contains $util.error(message) and outErrors array contains $util.appendError(message) messages.
Is this working as expected so the $util.error(message) will never show up in RequestMapping type CloudWatch logs?
Under what conditions will errors array in RequestMapping log type be populated?
Bonus question: can the errors array contain more than 1 item for either RequestMapping or ResponseMapping log types?