Snakes can definitely sense fear, and they know and respond to uncertainty. This is most likely what is happening with your interactions, perhaps compounding other possible issues mentioned such as approach and chemical odor etc.
Who normally interacts with the snake? Like feeding, water changes, spot cleaning, all that jazz. If it is your uncle who usually does these things, it may just be that his scent and presence have become recognizable to the snake, and she has learned through repeated exposure that he is not a threat to her. She may just be uncertain of you and fearful of the unknown, especially when you're afraid and uncertain of her too. In this case leaving a small article of clothing or object that has your scent on it inside the cage with her and/or building up small interactions (such as water changes and spot cleanings) should help aclimate her to you.
Im curious though, how did the leg bite occur? Like what do you think prompted it?