iPhone 16 pro max 26.0.1 ST4 1937
I was in portrait mode and with song list showing , I could not open mixer view at all, as song was playing I went to change view to lyrics as I touched the button the song started playing from beginning this has happened before randomly , then when I do get to lyrics view the mixer opens as expected and everything settles to normal behaviour.
My feeling is there is something wrong with the basic logic of operation causing other random issues.
Once that is fixed it might resolve all different quirks.
Good luck