Why would a girl go from been quiet to suddenly talking to a guy more?

This girl who knows me behaved like this. One minute she was fine with me and knows who I am as we've spoken heaps before. Next thing she went quieter with me and only me for no reason. She was fine with everyone else. Then after I helped her with something and made sure she was ok. The next time I saw her she and I locked eyes the moment I entered the room and we naturally just started chatting. The thing is the vibe between us felt like we were closer with each other. Please I need some advice as not many people are responding, hence the reason I've posted similar past questions

Why would a girl go from been quiet to suddenly talking to a guy more?
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