I have same issue as GameBear.

I have several of these stations in my city. Some work nicely. 2 don't work as expected. One of the two tubes gets plenty of passengers, the metros are full. The other tube doesn't get any passengers. Metros go there, metros stop there, and metros leave empty. I set up new lines to use them to see if that helps or changes anything. It doesn't.

Hmm, doesn't allow more than one stop on the same platform like a normal station does. I can only place one stop per platform even though there are 2 tracks in one platform.