Last nght I carved the attached pattern but was surprised when the CW proceeded to not only cut the arc through the board but also completly around the arc ending up as shown in the attachment cuting the ends completely. The actual board I used was longer and wider than the dimensions shown so I should have ended up with just a cut path in the board without the piece bing complelty cut off. I've used this cut path before to round off the ens of a pattern but not with these results.
What happened?