Hey mate,
The yellowing on new growth could be a wrong pH, so they cant take the feeding in. Its upwards your plant maybe, its light.
The other signs could be a Cal-Mag definciecy, but dont think so, you could add those to your feedingshedule. Knowing what you feed before im sure its no P-deficiency. If you feed 2/3 of the amount of nutrients, you can be sure it wont get worse, because of any overfeeding.
It also could be from overfeeding still, to stop it completly now you would have to flush your plant. and then give a regulated feed. Otherwise it will slightly go on for few days.
So check the pH of your feeding, It should be between 6-7 or slightly off. Also check the PPFD. And you could flush your plants on next watering.
Good luck mate