I've noticed that since this recent update the copier bugs up with multiple timing points either for flat-line BPM changes for multiple timing signatures or multiple BPM changes.
Try it out on http://osu.ppy.sh/s/94917 (my Iris map) and just copy one of the sounds between each other to get the odd bug.
Try it out on http://osu.ppy.sh/s/94917 (my Iris map) and just copy one of the sounds between each other to get the odd bug.