User data is getting mixed up

In the Android project I'm working on, we're noticing that user data is getting mixed up. Why could this be happening? Every time a user logs into the application, we perform a login to Intercom using the following code:

 

operator fun invoke(user: UserModel, intercomHash: String) {
    val userAttributes = createUserAttributes(user)
    val registration = Registration.create().withUserId(user.id)
    Intercom.client().setUserHash(intercomHash)
    Intercom.client().loginIdentifiedUser(registration, object : IntercomStatusCallback {
        override fun onFailure(intercomError: IntercomError) {
            /*
                The Intercom login will fail with error code 3002 if the user is already logged in.
             */
        }

        override fun onSuccess() {
            Intercom.client().updateUser(userAttributes)
        }
    })
}

private fun createUserAttributes(user: UserModel) = UserAttributes.Builder()
    .withEmail(user.person.emailAddress)
    .withPhone(user.person.phoneNumber)
    .withName(user.person.name.fullName)
    .withCustomAttribute(CUIT_CUIL, user.person.identification.cuitCuil)
    .withCustomAttribute(FIRST_NAME, user.person.name.firstName)
    .withCustomAttribute(LAST_NAME, user.person.name.lastName)
    .withCustomAttribute(EMAIL, user.person.emailAddress)
    .withCustomAttribute(DNI, user.person.identification.dni)
    .withCustomAttribute(TRACKING_ID, user.trackingId)
    .build()

And if the user unlinks their account, we use 

Intercom.client().logout()

Please note that we're using version 15.1.0 of the Intercom SDK.