Swift - playing videos in collection view cells

I'm using Swift to develop a mobile app. I'm playing videos in 2 Gemini collection views. Please see video of the flow:

However, I noticed that after a few 'users' are added, videos from both collection view cells start to disappear. See bellow:

See relevant code for BIG collection view:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "UserCollectionCell", for: indexPath) as! UserCollectionCell
        cell.setupUserNameAndVideo(userName: users[indexPath.row].name, userVideo: users[indexPath.row].picture)
        self.collectionView.animateCell(cell)
        return cell
}
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    if let cell = cell as? UserCollectionCell {
        self.collectionView.animateCell(cell)
        cell.playVideo()
    }
}
func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    if let cell = cell as? UserCollectionCell {
        cell.pauseVideo()
    }
}

See relevant code for SMALL collection view:

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "AvatarsCollectionCell", for: indexPath) as! AvatarsCollectionCell
        cell.setupUserNameAndVideo(video: avatars[indexPath.row].picture)
        self.avatarsCollectionView.animateCell(cell)
        return cell
}
func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    if let cell = cell as? AvatarsCollectionCell {
        cell.playVideo()
        self.avatarsCollectionView.animateCell(cell)
    }
}
func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    if let cell = cell as? AvatarsCollectionCell {
        cell.pauseVideo()
    }
}

Video player function in cell:

func setupUserNameAndVideo(userName: String, userVideo: String) {
                let path = Bundle.main.path(forResource: String(userVideo), ofType: "MOV")
                let pathURL = URL(fileURLWithPath: path!)
                let duration = Int64( ( (Float64(CMTimeGetSeconds(AVAsset(url: pathURL).duration)) *  10.0) - 1) / 10.0 )
                playerItem = AVPlayerItem(url: pathURL)
                player = AVQueuePlayer()
                player.volume = 0
                playerLayer = AVPlayerLayer(player: player)
                playerLayer.videoGravity = AVLayerVideoGravity.resizeAspect
                videoView.layoutIfNeeded()
                playerLayer?.frame = videoView.layer.bounds
                videoView.layer.insertSublayer(playerLayer, at: 1)
                playerLooper = AVPlayerLooper(player: player, templateItem: playerItem,
                                              timeRange: CMTimeRange(start: CMTime.zero, end: CMTimeMake(value: duration, timescale: Int32(0.00))) )
}

Also, play / pause functions in cell:

func playVideo() {
    player.play()
}

func pauseVideo() {
    player.pause()
}

Add user delegate function:

   extension SelectUsersViewController: AddUserDelegate {
        func userAdded(name: String, picture: String) {
            users.append(User(name: name, picture: picture))
            DispatchQueue.main.async {
                self.collectionView.insertItems(at: [IndexPath(row: self.users.count-1, section: 0)])
                self.collectionView.scrollToItem(at:IndexPath(item: self.users.count-1, section: 0), at: .centeredHorizontally, animated: true)
            }
        }
    }

I understand that looping multiple videos at once can be resource extensive. At first I though this might be memory issue, but it never reaches more than 100MB (which is ok in my opinion). Any other ideas?