If the song list is sorted by difficulty in-game and then any mods which affect difficulty are changed, the difficulty shown on the songs will be updated instantly but the overall sorting will not change. Currently the workaround I use is to change my list to a different sorting method and then change it back to sort by difficulty, which updates the list appropriately.
Grouping by difficulty is similarly affected, for example if a song is grouped under 2 stars and then Mods are changed which take it above 3 stars, it will still be grouped under 2 stars unless grouping is changed to something else and then back to difficulty.
Grouping by difficulty is similarly affected, for example if a song is grouped under 2 stars and then Mods are changed which take it above 3 stars, it will still be grouped under 2 stars unless grouping is changed to something else and then back to difficulty.