I can confirm this.
In this example you see a test playlist 2* music stereo, followed by news (mono) and again 2* music stereo.
All are normalised to -23 LUFS at -1 dBTP.
All music files are normalised correctly, the news (mono) file isn’t.
You can see it in the Container Waveform:
… and the result in the Analysis of the Orban Loudness Meter:
