I just noticed that when aligning regions, instead of “ends just meeting” they overlap a tiny amount of time and so are layered.
In one way it makes sense since the start of “Region B” and the end of “Region A” are at the same point in time, but on the other hand when splitting a region the new regions are also at the same point in time but stays side by side at the same level.
Did I accidentally change a setting or is this intended behaviour?