Leaf fringes turning brown

Thats obvious burn from nutes aka too rich feed. I would triple check pH too, some colour reminds issues with micros, that's ussually achieved by wrong ph , heavily wrong.

I see sign of overfeeding. Flush and give her less food...

I have a mimosa x orange punch and it can handle a lot of food, as much as you give it, it eats so much, it is literally impossible to feed it, the genetics of that species contains 70% of the species that you grow, so I think that the eat is right on the mimosa here... but if you think if you beat her, make a flush But again, I can't tell you exactly what the problem is because the plant shows most excesses and deficiencies very similarly...if I had grown it I would know what's wrong with it, it's very difficult for me to tell you, so don't listen to me. ..if you think you've overpowered her, do a flush and that's it...

I thing it's missing K,the plant does not look like that when it has excess N...and when there is an excess of some element in the plant, flush is done, if your pot is 40 L, flush is done with 120 L of clean water so that all the salts from the soil are cleaned. Also 0.75 l on a 40 l pot is very little... if the temperatures exceed 30 on that pot no problem from 5 to 10 L of liquid... I also think that you could add a small dose of cal-mag to them, it won't hurt them... I would also add Hesi Root throughout the growing season so that the plant can recover faster from stress and your roots will progress better, it will be for you very useful, if you are a beginner, it comes as first aid Happy grow bro!😁