While looking at the current gate map (Jade Falcon, Iron Queen, Emerald Lion, and Golden Sun) I noticed that at one point in the randomization, two of the exact same compound was loaded on the same depth, side by side. I can't say I've seen this happen before, with compounds or other levels, because there's usually at least some variation between the levels. (I.E., a change of minis for compounds, a change of status for monster strata, and a change of monster family for status strata.)
Here is a short album showcasing the two identical levels in comparison to other, seemingly identical levels that are actually different.