Nute burn or defience ?

The lowest/first leaves dying off is somewhat normal, I wouldn't stress too much, and some of the damage could be from hitting the string. To me it is not a P/K issue, just typical low leaf behaviour and quite expected in my experience.

I put water until runoff around %10.. ph is always around 6.2~6.5. Humidity around 45~50. They appeared 2 days ago i dont understand why… I thought too it may be pk defiency?

underwatering and bad humidity could cause it too btw, its first leaf set. Till you screw up once - they are best indicators Too little water makes N to go into salts and accumulation could arise , problems starts ...

Hello there:) It's P-K deficiency Probably too much N, that cause lack of pk :)

more ph and overwatering problem to me personally, i see no nute wise issue.