Each time I push any mute button of web UI, it properly mutes, but it also lowers predefined volume level by one or two. Both Volumio3 UI and Volumio2 UI. It only does not happen when initial volume level was 100. In this case volume level stays at 100. But if it was e.g at 95, then after pushing mute, it changes it to 94 and next time to 93 and then it stays at 93. SWhen starting at 90 it goes to 89, but then to 87, 86 and then it keeps this regardless of other mute pushing.
Volumio 2.657 on RPI3B+ with DAC HAT. One Click Volume Steps set to 5.
Hi Dede, this is due to a rounding function with logarithim volume… Hope that not bothers you too much since we can’t change that 
I can live with it if I have to. But can’t it just simply remember the number and then send it back after we push mute button or only after unmuting? If I can do it manually by "volumio volume " command, why app can’t do it similarly?