So I've already discussed it on Discord, but because nobody could give me an explanation, I thought I'd report it here. Today I found a bug with the splitters/mergers. When stacking them on top of each other, I can actually place another splitter in the exact same spot. So say it's the 2nd splitter/merger, If I do not aim up so I will place a 3rd one on top of it, I can actually keep placing them inside each other indefinitely on the 2nd position. A screenshot of it has been shared on the Discord on the 18th of December, 14:46 CET.
P.S. I can replicate the bug on other levels of stacking as well, but not on the bottom one.