Okay, that's strange. I haven't seen it yet but I can reproduce the behavior.
This is the initial setup: https://imgur.com/g5166Lc
If I build the lift to the right merger, it does not connect. Notice the gap: https://imgur.com/WyvKrre
If I deconstruct that lift and build it to the left merger, it snaps and items get transferred: https://imgur.com/YIGkYrL
But if I deconstruct that lift again and build it to the right merger, it does not "chirp" to confirm the connection, but it gets build as if it's connected, sending items still to the left merger: https://imgur.com/FQhe6cj
The issue has something to do with the "chirp". If I rotate the end of the lift while building it and it confirms alignment to the left merger, it then gets built as connected to it even though I rotated it to face the right merger. Without the "chirp", the lift stays disconnected.