Close with Tolerance not the same in Lightburn and MillMage

To fix an open path issue in this file, I copied it to Lightburn. I take advantage of Lightburn’s Fill mode. There the Close with Tolerance detected 1 open, and switched to closed at 1mm.

When I did the same in MillMage, Close with Tolerance would never switch. I clicked on Close Path, then the Close with Tolerance worked, also at 1mm. However, it still indicated 1 open along with 1 closed.

Is this a Bug or Undocumented Feature?

Thank you very much for your help. I was able to use Close path with tolerance in MillMage with success. I have only done a couple of projects in Lightburn and Millmage so i’m still a newbie.