Custom auth with adminInitiateAuth

Hello, my problem is that, Cognito isn't registering authentication events with adminInitiateAuth.

Here I have only access to username, so that's why I'm using CUSTOM_AUTH

AuthFlow: 'CUSTOM_AUTH',
AuthParameters: {
   USERNAME: username,
},
ClientId: clientId,
UserPoolId: userPoolId

It returns correct response (access token, refresh token), but it doesn't register Cognito authentication events in user details.

Table Last 100 authentication events is empty.

Tried with other AuthFlows and it worked, am I missing something?