I think that's normal. because after the ICO is completed and already distribution token usually bounty participants many who sell so the price will automatically fall. that's as far as I know. if there is less I may not understand.
I agree, also maybe there were such tokens whose price fell after entering the exchange.If the project will benefit the community, it will necessarily be successful, Nowadays, many altcoins, after entering the exchange, are falling in price, and only some of these altcoins restore lost positions.