AVAudioEngine playAndRecord noise over HDMI speakers

I am using AVAudioSession with playAndRecord category as follows:

private func setupAudioSessionForRecording() {
    let audioSession = AVAudioSession.sharedInstance()
    
    do {
        try audioSession.setActive(false)
        try audioSession.setPreferredSampleRate(Double(48000))

    } catch {
        NSLog("Unable to deactivate Audio session")
    }
    
    let options:AVAudioSession.CategoryOptions = [.allowAirPlay, .mixWithOthers]
    
    do {
        try AVAudioSession.sharedInstance().setCategory(AVAudioSession.Category.playAndRecord, mode: AVAudioSession.Mode.default, options: options)
    } catch {
        NSLog("Could not set audio session category \(error)")
    }
    
    do {
        try audioSession.setActive(true)
    } catch {
        NSLog("Unable to activate AudioSession")
    }
   
}

Next I use AVAudioEngine to repeat what I say in the microphone to external speakers (on the TV connected with iPhone using HDMI Cable).

 //MARK:- AudioEngine

var engine: AVAudioEngine!
var playerNode: AVAudioPlayerNode!
var mixer: AVAudioMixerNode!
var audioEngineRunning = false

public func setupAudioEngine() {
    
    self.engine = AVAudioEngine()
    
    engine.connect(self.engine.inputNode, to: self.engine.outputNode, format: nil)
    
    do {
        engine.prepare()
        try self.engine.start()
    }
    catch {
        print("error couldn't start engine")
    }
    
    audioEngineRunning = true
}

public func stopAudioEngine() {
    engine.stop()
    audioEngineRunning = false
}

The issue is I hear some kind of reverb/humming noise after I speak for a few seconds that keeps getting amplified and repeated. If I use a RemoteIO unit instead, no such noise comes out of speakers. I am not sure if my setup of AVAudioEngine is correct. I have tried all kinds of AVAudioSession configuration but nothing changes.

The link to sample audio with background speaker noise is posted [here] in the Stackoverflow forum (https://stackoverflow.com/questions/72170548/echo-when-using-avaudioengine-over-hdmi#comment127514327_72170548)