I think I noticed this earlier and you probably fixed it, but I have v.5.1.25 dev. loaded and notice that if I program a lead out, the overcut length is followed. If I remove the lead out, the overcut length doesn't seem to be used. It is as if the overcut was 0mm even though I have it set to 3mm.
The short lead out is how I took care of this which also reminded me that the lead out length needed is somehow related to kerf entry of the tool for the overcut length to be employed - If that helps.
A 1.8mm kerf needs a 1.35mm lead out. A 1.5mm kerf needs a 1.125mm lead out.