Well it could certainly be a bug. But if you've narrowed it down to the orient constraint, then perhaps you can just try avoiding using that by using xform to orient your object or, since it looks like you are using PyMEL:
Also, as a side note I really recommend putting your PyMEL into a namespace. The original tutorial says importing as * works, but then you end up unable to properly filter and find PyMEL functions. For example, if you use the pm namespace, you can always search "pm." to find PyMEL functions, as distinct from variable names. It will make your code much more readable and upgradeable, if you ever need to find and replace functions with alternatives.