The E-Series prototype boards were going to assembly at my PCBA house when they discovered a problem. The linear voltage regulators did not fit on the footprint. After having a minor heart-attack I looked at the picture they sent and understood what happened. I had given them the wrong part numbers. They were off by one letter. I gave them part numbers for a different physical package. Thanks to the picture they sent it was easy to remedy. Always double-check your BOM before manufacture. This was not a big deal because it's just 16 components and they are very cheap. But it did delay assembly another week while they source the correct parts.
On the bright side it was nice to see a picture of the prototype PCBs :)