MongoDB automatic (implicit) CSFLE broken with Micronaut 3

I've recently updated my app from Micronaut 2 to Micronaut 3, and as a result all Mongo automatic CSFLE encryption/decryption has stopped working.

If I create a ClientEncryption object and manually decrypt the field, that works, and the logging shows that it is fetching KMS and key information needed to decrypt it:

INFO org.mongodb.driver.client - executeStateMachine: READY
INFO org.mongodb.driver.client - executeStateMachine: NEED_MONGO_KEYS
INFO org.mongodb.driver.client - executeStateMachine: NEED_KMS
// manual decryption result here

But for the automatic process, it just prints the READY state only, and no encryption/decryption takes place.

Is there any examples showing automatic CSFLE working with Micronaut 3, or has anyone run into this issue? Could this be a bug with Micronaut 3?

The two relevant dependencies in the Micronaut 3 upgrade are:

implementation "io.micronaut.mongodb:micronaut-mongo-reactive:4.2.0" // driver
implementation "org.mongodb:mongodb-crypt:1.5.2" // uses libmongocrypt

and the mongodb-enterprise-cryptd v5.0.6 binary is installed on the ubuntu:20.04 OS that we're running the app on. The mongocryptdSpawnPath extra options property in the Mongo connection is pointed at the location of the installation.

• Server version: Enterprise 4.2.21

I can't give exact schemaMap and DB details, but here is a similar one generated by the same code, for a DB called zoo and two collections using CSFLE called dogAnimals and catAnimals.

sample dogAnimals document:

{
    "basicDetails": {
        "dogName":"Barney", // should be encrypted
        "age":5,
    },
    "furtherDetails": {
        "dogBreedInfo": { // should be encrypted
            "breedName": "Golden Retriever",
            "averageLifeSpanInYears": 20
        }
    }
}

sample catAnimals document:

{
    
    "catName":"Mrs Miggins", // should be encrypted
    "age":2,
    "catFacts": {
        "favouriteHuman": "Robert Bingley", // should be encrypted
        "mood": "snob"
    }
}

Matching schemaMap:

{
    "zoo.dogAnimals": {
        "bsonType": "object",
        "encryptMetadata": {
            "keyId": [
                {
                    "$binary": {
                        "base64": "12345678",
                        "subType": "04"
                    }
                }
            ]
        },
        "properties": {
            "basicDetails": {
                "bsonType": "object",
                "properties": {
                    "dogName": {
                        "encrypt": {
                            "bsonType": "string",
                            "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Deterministic"
                        }
                    }
                }
            },
            "futherDetails": {
                "bsonType": "object",
                "properties": {
                    "dogBreedInfo": {
                        "encrypt": {
                            "bsonType": "object",
                            "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
                        }
                    }
                }
            }
        }
    },
    "zoo.catAnimals": {
        "bsonType": "object",
        "encryptMetadata": {
            "keyId": [
                {
                    "$binary": {
                        "base64": "12345678",
                        "subType": "04"
                    }
                }
            ]
        },
        "properties": {
            "catName": {
                "encrypt": {
                    "bsonType": "string",
                    "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
                }
            },
            "catFacts": {
                "bsonType": "object",
                "properties": {
                    "favouriteHuman": {
                        "encrypt": {
                            "bsonType": "string",
                            "algorithm": "AEAD_AES_256_CBC_HMAC_SHA_512-Random"
                        }
                    }
                }
            }
        }
    }
}