Hello,
we updated Lightburn to the newest version today. Since today, when importing from FreeCad, we noticed there are ‘invisible’ double lines. Because when we use the ‘delete duplicates’, there is nothing to be found. But when I use the select tool and then click on the edit nodes, I can discover the double line by deleting it and seeing that a line remains underneath.
Even when drawing a rectangle, and I duplicate it to have another, the duplicated square now suddenly has double lines. I think this is really strange. It’s quite problematic because we have a production and I can see how to fix this. I am deleting double lines manually now for every object I need. Crazy 
Thanks for advice, if this is related to the newest update.
I can not upload because it is not supported (technical drawing).