Hi guys any clue what's going on here please

Next time it needs watering just go back to your regular feed schedule.

Yeah I flushed it yesterday just thinking when I should give it nutrients

I had a plant look like that in week 3 of flower. Turned out to be a Potassium deficiency caused by nutrient lock out (Too much salt in the soil). A good flush took care of the problem and the new growth came in fine.

Thanks for the replies

I concur. :)

Looks like calcium deficiency. More info: https://www.mrgrowit.com/post/calcium-deficiency-in-cannabis-plants