I cannot repro on our latest beta (Discourse 2.3.0.beta9). @Rahul_Goswami I see you are currently on Discourse 2.3.0.beta8. Can you try updating your site and see if the problem persists?
I’ve currently tried creating a topic with a matching title and tags. I’ve added and removed tags through the title edit method and through the composer editor with no change to the url.