Honey's darkening

Hello ! I'm no beekeeper but my cousin is. I've helped her for her harvest 2y ago or so, in the lower Alps in the south of France, and she gave me a lot of honey. It's lavender honey. I''ve forgotten some pots and I've noticed that 3 of them were darkening, especially one that's completely dark. I've wanted to know if you knew the reason of this phenomenon and if the honey was still consumable? Thanks for your attention 😁😁