Auriclux,
Looking at the last image attached in your first post, it appears that you have a 1/4" thick board taped to a larger (width and length) board to get a thickness recognizable by the machine. Is this correct? Did you run it through the machine this way? If I'm looking at the picture correctly, I would think that when the machine is finding the top of the board it will measure to the top of the bottom board and not to the top of the board you are carving. So when it starts to carve, the machine thinks the top surface is 1/4" below the board you are trying to carve. This may be the cause of your carve-through issues on your switch plates, and why it choked on the last one. The rollers may have dropped off your 1/4" piece down to your carrier piece causing an error. Trying taping up a 1/4" board to a carrier board that has the same length and width. Thin double sided carpet tape works great for this. Be careful with any cutouts (Don't do any), as the machine will cut through both boards and your top 1/4" cutout will NOT be attached to anything and will come loose with the potential of breaking a bit or worse. The cutout tabs will only secure the bottom piece of your sled.
Hope this helps.