2D Engrave fails on circular contours

[aa7bq]

I have made an example project to illustrate this behavior.  See  http://a360.co/2lMzcFs

I first discovered than on an engraving job that contained a number of circular features (dots), that some of the dots were being silently dropped out of the chain.  There was no indication of anything wrong from F360, but the results beg otherwise.

I begin this exercise with an ordinary body having a 5x5 grid of holes.   In Engrave, I selected all of the hole contours along with an ordinary 45 degree chamfer bit.

Now here's where it fails.   The toolpath in this instance only found 3 of the holes out of 25.   These holes were created with a rectangular pattern in sketch mode and are all identical.   Whats worse is that the behavior isn't consistent.  Sometimes the Engrave routine will find more, or fewer holes, but never all of them.   Sometimes, if the body is edited, made larger or smaller, the number of holes chained will change.  Oddly, non-circular holes do not have this problem.   For example, if I create a center-to-center slot with 0.001 between the centers, Engrave has no problem with that.   The problem only manifests itself with circles.   

 The holes which were chained produce the expected result and engrave correctly.   The problem is that it silently drops features that are circular.  

While I'm new to Fusion 360, I'm a professional software developer of 25 years.  This looks like a bug.

Again, this project has been made public at:  http://a360.co/2lMzcFs

Thanks in advance,

-fred

[seth.madore]

Yeah Mark, considering this is the second time in as many weeks that this has cropped up....