Is ignite bugged or is this just some janky shit?

Sometimes when using ignite you don't always follow the enemy as they run or continue attacking/chasing, there is a delay like the game needs to register that there are things to attack and you might just start attacking creeps if you dont give command to attack. Ive seen many ppl flash and just stand there and ppl either have time to flash or get away. tested it multiple times in practice tool where ill be in combat, the bot runs, ive right clicked them so im chasing but im also hitting ignite and after ignite goes off i just stand there.