Guy's Behavior

Ex is acting hot and cold?

So I was seeing this guy for about a month, he completely initiated the relationship and chased me, planned all our dates etc. We had amazing chemistry, he treated me so well and all seemed to be falling into place (genuinely thought it was heading towards a relationship). However, he then suddenly cut it off, saying he wasn't looking for commitment right now (i personally think he got a bit scared as we are both in our final year of uni so moving on soon). It didn't end on bad terms by any means, although naturally i was upset in private. We then had a few weeks of no contact, before he started sporadically messaging me again asking about uni work. Over the next couple of weeks, he started reaching out more and more, and said a few slightly suggestive things, but all conversations were loosely based around uni work. We then both had to attend a uni class together. However, when we got into the class he completely ignored me, barely saying hello but he was being massively overfriendly to everyone else in the class which is very out of character (peacocking?). No one in the class knew we were an item at one point in time. I assumed he just was no longer interested, however after the class was over he waited outside for me and started chatting and flirting on our walk home (brushing shoulders, eye contact, making in jokes etc). This was just under a week ago, haven't heard from him since. Why would he act so hot and cold towards me, especially in public? He ended the relationship but his actions seem to suggest that he's still not over it? Any advice would be massively appreciated :)
Ex is acting hot and cold?
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