I don't know if this is already a known issue, but I figured out, that the magical exchange of an stone ax or golden ax with Lucy (If she lays on the ground) is giving you back another ax than you used before.
Before chopping with golden ax
After Chopping once Lucy is equipped, the golden ax is gone and a stone ax appeared.
the new stone ax spawns with 100% durability.
If you put Lucy back on the ground and take one of the stone axes to cut a tree, the golden ax will reappear, but the stone ax is gone.
Maybe it doesn't matter because Lucy has infinite shelf life or there is a reason to design it this way but it struck me as strange.
Play Woodie First, put Lucy the ax on the ground Second, take another ax with a durability that is not 100% (it is better to see that it is really a different ax) Third, try cutting down a tree so Lucy is back in your inventory Take the ax that appeared where Lucy was lying. To get your original ax back, just repeat the process.