Erebus nightcrawlers bug

I was playing a custom game as Erebus when I noticed that two of my nightcrawlers were stuck in the citadel. They were selectable and they had the walking animation, but weren't moving anywhere. Later in the same game a minion was stuck out in empty space off the path. Again, it was selectable and animated but not going anywhere. After I died the minions went away as usual.

I've only noticed this happening in that one game so far.