If I'm reading your post right and your ec is 1.8 that is way too high it should be around 0.8 for the stage your at, that will be causing the nute burn your seeing. If I'm reading your post wrong and it's not at 1.8 then I have no idea 🤷♂️
Thanks pal I'm only going for the 8 colas which I've achieved now so I'm only going to veg them for an extra week 5 weeks in total veg time, plus the 2 weeks in seedling stage, so 7 weeks in total since putting in the ground is what I'm aiming for