Hello ! Your plant looks healthy to me , you' using a mix between light mix and bat mix so your plant should had enough nutrients for the 3 first weeks , I can see that you used Algua grow at half of the recommended chart which is a smart mouve however I don't bet on a Nitrogen toxicity , your plant would have been more dark green than that. No nutrients burn neither , to me your tips are not even yellow but pale green , let the new leaves the time to get bigger and if the yellowing spreads then you will have to worry. Also agreed with bulbi , you should hve continue the grow nutrients untill the 2nd week of flowering ( but if a nitrogen toxicity is proven then it's the best thing you could have done). I hope it will help you 😁👍