At first I thought it was me when I saw fades disappearing on events I did not touch. In order to see this problem you must set Show Unquantized Event Start and Set Unqauntized Event Stop to True in Preferences < Internal by selecting Options then holding the shift key while selecting Prefererances. Then select the Internal tab and set both to True. Load a project with a many events and see all the red bands identifying unquantized events. Add a fade out to the end an event with a red band at the end. Edge edit a downstream event with a red band at the start and watch your fade disappear. It does not occur every time but more often than not. This is not the only side effect of the unquantized event starts and ends.

Ed B