What I found out is that the click gets ignored when you zoom and then click the middle button while the zoom animation is still running. However, you can zoom and turn simultaneously fine if you click first.
Also, it does not work when the cursor is over a mining tower infobox (the one that shows how many excavators and trucks are assigned), or forestry tower info box. Neither does zoom in that situation. Zooming and turning should ignore those boxes.
Edit: v0.8.6a but was the same in 0.8.5