Done. I was able to reduce the tracks down to 5 second cuts and still reproduce the problem. Submitted as ticket #6183.

Can you please offer the 2 files to Support? You may have to upload to a cloud service as FLAC files tend to be too big to attach.

I am using MMW 5.0.4.2690 and using the DirectSound output.
I cannot reproduce the problem if selecting the WASAPI output.
I can reproduce the problem if selecting the "waveOut output v2.0.2a".

is Play > Level playback volume enabled?

Yes, however the problem is reproducible even if it is not enabled.

Are you saying this is consistently reproducible between 2 tracks?

Yes, given the selection of two tracks, the screech is reproducible every time.

Which Build (Help > About) of MediaMonkey, which Output Plug-in and is Play > Level playback volume enabled?

Are you saying this is consistently reproducible between 2 tracks?

At the end of some tracks a short but loud screech plays.
I cannot hear any sound like that if I play the track in VLC. And it seems to be influenced by what which plays next. If I find a sequence of two tracks that exhibit the problem, and exchange one of the tracks for another, the problem goes away. So far I think I have only heard the problem between two FLAC tracks.

It does not occur often but if it does when using headphones and having raised the volume a bit... Oh boy...

I will submit a bug report if the problem is not known or fixed yet.