Drogon's Winter Wind ability doesn't work

Hi,

In my last game a few weeks ago, playing with the Tinkerer, I had Drogon as my main hero and his Winter Wind ability mostly worked. I had just one instance where it didn't (casting spell & animation work but he's not teleporting) and had to reload from an earlier save.

However in the current game with the Wizard I'm actually stuck. I tried everything but he just isn't able to teleport. Save game in the link.

Edit: It's not only Drogon, it's also Korthox.

Thanks.