MediaElements consume large amount of memory

Question

A few days ago I posted here a question, where I complained that my game consumes way too much RAM.

The game I am making consumes way too much memory

Among the answers and comments, I got recommendation to check what exactly in my game causes this, and specify the exact problem.

I have used VS2017 built-in tools, and found out, that the majority of memory is consumed by MediaElements.

I indeed have a huge number of MediaElements, the majority of which are voiceovers.

I already set their all sources to null, then made the game to load the source of relevant file only when it's played, resetting it to null when done.

voice_path.Add("vcoCombine_armed_slingshot_canned_food", vcoCombine_armed_slingshot_canned_food.Source.ToString());

vcoCombine_armed_slingshot_canned_food.Source = null;

    public void AssignPathVoice(MediaElement vcoThis)
    {
        if (voice_path.ContainsKey(vcoThis.Name.ToString()))
        {
            string path = voice_path[vcoThis.Name.ToString()];
            vcoThis.Source = new Uri(path, UriKind.Relative);
            vcoThis.Play();
        }
    }

It helped reduce much of memory usage, but still not enough.

What can be done to reduce memory usage by MediaElements?

I tried using ".Freeze()" like people recommended to do with images, but couldn't do it, neither as:

vcoSomething.Freeze();

nor as:

vcoSomething.Source.Freeze();

Is there a way to reduce memory used by MediaElements more then now?

Thank you,

Evgenie

UPDATE: What I tried so far:

1) Stay with just one MediaElement, and change its source, it didn't help.

2) Change source files from WAV to MP3. This reduced hard disk memory consumption, but not RAM.

3) Tried finding if I have a memory leak. Took a memory snapshot while game was running. I get the "Hashtable [Cycle Detected]" also somehow connected to MediaElements. I read that it means that I have some kind infinite loop. But I can't find where it can be.