Burnt tips

Not deficiency or over watering..........just damage from hitting something, either the sides of the pots or the soil surface, usually at night when the leaves lowered down.

Your leaves had been in contact with water or wet soil on earlier stage. Your baby Is fine let her grow and do her thing

I am going to agree with terptime here the way it started with a bit of yellow then transitioned to brown and dried looks like it definitely got some nute burn i would recommend doing a flush and check the ec/ppm and see what the run off is like the soil you use may be hurting it depending on what you have and do you ph down your RO water? But hopefully this will help also if you have some kind of beneficial microbe i would recommend adding it during the flush they will help to fix things.

yep could be deficiency if it shows on bottom leaves it's time to give em 300 ppm

Looks like a slight burn. Make sure your plants are receiving around 300–500 µmol/m²/s. What kind of soil are you using?