distortion when recording streaming with Loopback selected

Windows 10
Audacity 2.4.0 (this problem occured with 2.3.3 and 2.4.0)
I have been recording Spotify streamed music.

First, using the recommended setup, ie WASAPI/Loopback/Stereo recording:
In spite of adjusting the audio level at source (Spotify) and/or via the Windows mixer controls during recording, a “thump” is heard during playback at many of the audio peaks. (Audacity record level is disabled in this mode). This “thump” noise is not heard on my speakers whilst recording. It is not indicated as clipping either (and clearly isn’t).

So, I tried the alternative setup: WASAPI/Stereo Mix/Stereo recording: In this mode, the problem disappears (using the same audio material). This means that the distortion is not a Playback problem.

I would prefer to record using the recommended setup, for max fidelity.

Help welcome!

Perhaps you could post a short example - just a few seconds in WAV format (see: https://forum.audacityteam.org/t/how-to-post-an-audio-sample/29851/1)