why does he act so RUDE?? strange BEHAVIOUR?? boys please help me?

Hes super quiet around me, not like he is with other girls, ive seen him interacting with them, and hes much more social. He mostly answers my questions and then asks me the same questions back. If I dont say anything, he basically wont ask anything and starts playing around with his phone when we both get silent and it gets awkward. He plays with his phone when we are talking sometimes too, but he looks at me when he talks and when I answer his questions. He does get smiley and or so it seems happy when I say hi or whatever, mostly i initiate, but his behavior confuses me especailly this next part. He tends to run away or avoid me alot of the time, sometimes just me, or sometimes both me and my friend (who he also knows). The latest incident would be the other day, we were almost parallel, I was looking at my phone, and him at his, and im sure he saw me. He walked a bit ahead when we got close, and then totally turned at a random corner, not where he was supposed to go. I totally felt he did that on purpose, him running ahead and turning like that was just too weird. And then when we got off the bus and were at the stop he ran to his car before I got even close to him ( he does run when his mom is around for some reason, dont know if hes scared of her). I dont mind if he doesnt like me, but i really would like to know what i did?? ive never been rude to him and honestly this behavior hurts so please help!?