I will try to explain it by screenshots:
https://imgur.com/a/Diw5TL3 - in this situation I cannot connect right side of output to merger. I tried from different angle but still cannot connect them ;/
One more thing that from left side of splitter output when I connect it goes from splitter green arrows. From right side of splitter it try connect from merger to splitter with goes on orange arrows that make it impossible to connect. Probably because of difference between splitter and merger.
https://imgur.com/a/JbuvRsN - here I came up on idea to move further to left side with allow me to connect with right side... but it does not looks good :|