@too, can you please try to pick at that linear feature with the tip of a wooden toothpick? If nothing happens then those are probably die cracks. I can't tell from the pics if that is what they are or else thin strands of dried glue.
"If you climb a good tree, you get a push."
-----Ghanaian proverb
"The danger we all now face is distinguishing between what is authentic and what is performed."
-----King Adz