My ex-GF told me to keep the keys to her place?

My ex-GF had me leave her house for 3 months of space, we share a child together. This is the same ex-GF from my last post. The night before I left, she told me I could keep the set of keys I had but to not stick around, and only call her first before coming over. She also mentioned that her dad may want to change the locks (which I believe is non of his business since it is not his house and it isn’t his life or decision over who his daughter allows on her property) and that if he does she will just give me a new set of keys. I’m confused about all of this. Why not just take her keys back?
My ex-GF told me to keep the keys to her place?
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