It seems that as of v2.0, module files with loop points no longer loop properly when played back using the ModPlug or DUMB plugins. Upon reaching either a loop point or the end of the song, the player stops and reloads the file before playing it back from the beginning, causing a very large gap in playback. This happens regardless of the "endless playback" setting. It's a shame, because now I can't zone out to seamlessly looping songs on the bus anymore. :(
Other formats with loop points (e.g. SPC files) do not exhibit this behavior, nor does the UADE plugin.