Delve mineshaft bugged at depth 10/11

So my mineshaft seems to end at depth 11 and the line doesn't connect all the way to the depth 11 node(armor items).

If I try to go there with the cart it just goes on without any monster spawning and then it stops in an empty space with nothing happening(and it doesn't "complete" the section and I can't click the cart).

This is because the central mine shaft that Niko digs is incomplete as he progresses it as you complete the main story.