Here's another picture of the tiles (now showing the completed wall) and you can probably see lots of zig-zags - or at least I can:
Since neither I nor my husband was home to see the actual tile, we were relying on the cell phone picture of the tile. The message to fix the tile was routed through our contractor and then to the tile guy. When the tile guy looked at the tile, I'm sure he thought we were nuts, but he moved a few of the small tiles anyway. He asked his assistant to take a picture to send to the contractor but when the assistant prepared to take the picture he got a screwy look on his face as he looked from the camera to the tile and back again. Now they saw what we saw!
So mystery solved. The tile is just fine and we've all learned that pictures can lie, especially when it's a picture of glass mosaic tile!