I can confirm that it happens also to me and also when turning off the PC.
So it doesnt have to do with the driver or TotalMix FX.
Only for reference here: 2 UFX+: both SW v37, Driver 0.9610, TM 1.42
To trigger the issue: you simply need to turn the know left/right 1 position repeatedly.
Around 0 - -15dB no deltas, but the lower you get the more deltas you get up to 10dB around -40 / -50 dB.
But it was never a problem for me, as I turned down the volume of my Main Monitors so much,
that 0dB are loud, but do not hurt my ears.
For Main Out and Phones I use these settings:
Main Out:
- Output Level: +4 dBu
- Fader Level: -20dB
Phones:
- Output Level: Low
- Fader Level: -25dB
By this I have enough headroom
- starting from relatively quiet when just powering on the system
- up to good listening volume
So I would advice you to work on the Levels and bring this more into balance.
In the case that somebody has Monitors without Volume Potis this might become nasty, as some monitors have very high output to get very good sound at normal levels. These of course could force a user to work with -40dB where this issue could lead to noticeably volume differences.
If RME could find a solution for this would be nice.
I think this is more SW / Firmware related, as at the end you turn an encoder always between 2 states.
The behaviour changes with the volume range in which you do the left/right movements.
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14