MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
That is probably because your nozzle is too close to the printing bed when it prints the first layers which causes them to squeeze out sideways and thus making the peg-hole on the bottom side too tight. (Ok, that sounds so wrong... ^^)
The file is perfectly symmetrical. Look for troubleshooting when over-extrusion happens.It should be a question of re-leveling the plate. :-)