It looks like you’re using the Export As function on the Mac. Keep in mind, Glowforge recommends the use of Save As; although, a few of us stick with Export.
I’ll second this - I had some issues with “Save As” and I find “Export As” much more consistent. In particular, Export saves out the dimensions while Save As doesn’t so the GFUI occasionally does odd things with sizing because it’s trying to guess. And Export strips out “hidden” things, which is useful for my designs because I make things with many hidden layers (for a given job) in my workflow - each job’s variations from a template are in their own layer, so I have files with 50 layers, only two of which are visible for a given export. Of course, GF recommends Save As, because that’s what they QA, so YMMV.
I’ve been using 4 digits, and turning on minify. One more digit of resolution is at worst a waste of a little disk space, and minify makes files smaller without changing the meaning, and that seems to work, too.