The use ability star dosnt always show on the creature. It dose on the enchantment not on the creature. For instance this time the creature was on the right of the field but the ability icon was midfield in an empty hex.

I've also experienced a bug where I cast the Chain on a building in the fog (i.e. the building has 0 vision, and I couldn't see anything around the building). The Chain disappeared after I cast it. Later on I realized it was somehow attached to my enemy's building, which was right beside my building that I had targeted. Mind you, that's before I even knew there was a building there. It otherwise worked fine from then on.