Just to add that I also have this issue and I have 4 first revision DSWs of various ages.

Not sure that I can add any value to this thread but I have noticed that nobody seems to have tested between music and movie modes. Something I will try myself if I ever get the time.

Sources: MS600, Fidelity Audio Reference Oppo UHD-203, Roon/QNAP, AppleTV 4K
Processors: Arcam AV40, 271 x2, Lumagen 5348 with Keces P8
Speakers: DSP7200SE FL/FR, DSP5200SE VC, DSP3200 x11, DSP320.2 VOG, DSW x4
Display: JVC DLA-N7 with PK-EM2, Panamorph Phoenix Pro, 128" 2.37 Curved Silver Ticket AT Screen